Thomas Hobbes

From Wikipedia, the free encyclopedia

 

Thomas Hobbes
Born	(1588-04-05)5 April 1588 Westport near Malmesbury, Wiltshire, England
Died	4 December 1679(1679-12-04) (aged 91) Derbyshire, England
Era	17th-century philosophy (Modern Philosophy)
Region	Western Philosophers
School	Social contract, classical realism, empiricism, materialism, ethical egoism
Main interests	Political philosophy, history, ethics, geometry
Notable ideas	Modern founder of the social contract tradition; life in the state of nature is "solitary, poor, nasty, brutish and short"
Influences	[show] Aristotle, Thucydides, Tacitus, René Descartes, Grotius, Niccolo Machiavelli
Influenced	[show] Western political philosophy and sociology

Thomas Hobbes of Malmesbury (/hɒbz/; 5 April 1588 – 4 December 1679), in some older texts Thomas Hobbs of Malmsbury,^[1] was an English philosopher, best known today for his work on political philosophy. His 1651 book Leviathan established social contract theory, the foundation of most later Western political philosophy.^[2]

Though on rational grounds a champion of absolutism for the sovereign, Hobbes also developed some of the fundamentals of European liberal thought: the right of the individual; the natural equality of all men; the artificial character of the political order (which led to the later distinction between civil society and the state); the view that all legitimate political power must be "representative" and based on the consent of the people; and a liberal interpretation of law which leaves people free to do whatever the law does not explicitly forbid.^[3]

He was one of the founders of modern political philosophy and political science.^[4][5] His understanding of humans as being matter and motion, obeying the same physical laws as other matter and motion, remains influential; and his account of human nature as self-interested coöperation, and of political communities as being based upon a "social contract" remains one of the major topics of political philosophy.

In addition to political philosophy, Hobbes also contributed to a diverse array of other fields, including history, geometry, the physics of gases, theology, ethics, and general philosophy.

Early life and education

Thomas Hobbes was born at Westport, now part of Malmesbury in Wiltshire, England, on 5 April 1588.^[6] Born prematurely when his mother heard of the coming invasion of the Spanish Armada, Hobbes later reported that "my mother gave birth to twins: myself and fear."^[6] His childhood is almost a complete blank, and his mother's name is unknown.^[7] His father, also named Thomas, was the vicar of Charlton and Westport. Thomas Hobbes Sr. had an older brother, Francis Hobbes, who was a wealthy merchant with no family of his own. Thomas Hobbes, the younger, had one brother Edmund who was about two years older than he. Thomas Sr. abandoned his wife, two sons and a daughter, leaving them in the care of his brother, Francis, when he was forced to flee to London after being involved in a fight with a clergyman outside his own church. Hobbes was educated at Westport church from the age of four, passed to the Malmesbury school and then to a private school kept by a young man named Robert Latimer, a graduate of the University of Oxford. Hobbes was a good pupil, and around 1603 he went up to Magdalen Hall, which is most closely related to Hertford College, Oxford.^{[8][9][10][11]} The principal John Wilkinson was a Puritan, and he had some influence on Hobbes.

At university, Hobbes appears to have followed his own curriculum; he was "little attracted by the scholastic learning". He did not complete his B.A. degree until 1608, but he was recommended by Sir James Hussey, his master at Magdalen, as tutor to William, the son of William Cavendish, Baron of Hardwick (and later Earl of Devonshire), and began a lifelong connection with that family.^[12]
Hobbes became a companion to the younger William and they both took part in a grand tour of Europe in 1610. Hobbes was exposed to European scientific and critical methods during the tour in contrast to the scholastic philosophy which he had learned in Oxford. His scholarly efforts at the time were aimed at a careful study of classic Greek and Latin authors, the outcome of which was, in 1628, his great translation of Thucydides' History of the Peloponnesian War, the first translation of that work into English from a Greek manuscript. It has been argued that three of the discourses in the 1620 publication known as Horea Subsecivae: Observations and Discourses, also represent the work of Hobbes from this period.^[13]

Although he associated with literary figures like Ben Jonson and thinkers such as Francis Bacon, he did not extend his efforts into philosophy until after 1629. His employer Cavendish, then the Earl of Devonshire, died of the plague in June 1628. The widowed countess dismissed Hobbes but he soon found work, again as a tutor, this time to Gervase Clifton, the son of Sir Gervase Clifton, 1st Baronet. This task, chiefly spent in Paris, ended in 1631 when he again found work with the Cavendish family, tutoring the son of his previous pupil. Over the next seven years as well as tutoring he expanded his own knowledge of philosophy, awakening in him curiosity over key philosophic debates. He visited Florence in 1636 and later was a regular debater in philosophic groups in Paris, held together by Marin Mersenne. From 1637 he considered himself a philosopher and scholar.^{[citation needed]}

In Paris

Thomas Hobbes

Hobbes's first area of study was an interest in the physical doctrine of motion and physical momentum. Despite his interest in this phenomenon, he disdained experimental work as in physics. He went on to conceive the system of thought to the elaboration of which he would devote his life. His scheme was first to work out, in a separate treatise, a systematic doctrine of body, showing how physical phenomena were universally explicable in terms of motion, at least as motion or mechanical action was then understood. He then singled out Man from the realm of Nature and plants. Then, in another treatise, he showed what specific bodily motions were involved in the production of the peculiar phenomena of sensation, knowledge, affections and passions whereby Man came into relation with Man. Finally he considered, in his crowning treatise, how Men were moved to enter into society, and argued how this must be regulated if Men were not to fall back into "brutishness and misery". Thus he proposed to unite the separate phenomena of Body, Man, and the State.^{[citation needed]}

Hobbes came home, in 1637, to a country riven with discontent which disrupted him from the orderly execution of his philosophic plan. However, by the end of the Short Parliament in 1640, he had written a short treatise called The Elements of Law, Natural and Politic. It was not published and only circulated among his acquaintances in manuscript form. A pirated version, however, was published about ten years later. Although it seems that much of The Elements of Law was composed before the sitting of the Short Parliament, there are polemical pieces of the work that clearly mark the influences of the rising political crisis. Nevertheless, many (though not all) elements of Hobbes's political thought were unchanged between The Elements of Law and Leviathan, which demonstrates that the events of the English Civil War had little effect on his contractarian methodology. It should be noted, however, that the arguments in Leviathan were modified from The Elements of Law when it came to the necessity of consent in creating political obligation. Namely, Hobbes wrote in The Elements of Law that Patrimonial kingdoms were not necessarily formed by the consent of the governed, while in Leviathan he argued that they were. This was perhaps a reflection either of Hobbes's thoughts concerning the engagement controversy or of his reaction to treatises published by Patriarchalists, such as Sir Robert Filmer, between 1640 and 1651.^{[citation needed]}

When in November 1640 the Long Parliament succeeded the Short, Hobbes felt he was a marked man by the circulation of his treatise and fled to Paris. He did not return for eleven years. In Paris he rejoined the coterie about Mersenne, and wrote a critique of the Meditations on First Philosophy of Descartes, which was printed as third among the sets of "Objections" appended, with "Replies" from Descartes in 1641. A different set of remarks on other works by Descartes succeeded only in ending all correspondence between the two.

Hobbes also extended his own works somewhat, working on the third section, De Cive, which was finished in November 1641. Although it was initially only circulated privately, it was well received, and included lines of argumentation to be repeated a decade later in the Leviathan. He then returned to hard work on the first two sections of his work and published little except for a short treatise on optics (Tractatus opticus) included in the collection of scientific tracts published by Mersenne as Cogitata physico-mathematica in 1644. He built a good reputation in philosophic circles and in 1645 was chosen with Descartes, Gilles de Roberval and others, to referee the controversy between John Pell and Longomontanus over the problem of squaring the circle.

Civil war in England

The English Civil War broke out in 1642, and when the Royalist cause began to decline in the middle of 1644 there followed an exodus of the king's supporters to Europe. Many came to Paris and were known to Hobbes. This revitalised Hobbes's political interests and the De Cive was republished and more widely distributed. The printing began in 1646 by Samuel de Sorbiere through the Elsevier press at Amsterdam with a new preface and some new notes in reply to objections.

In 1647 Hobbes took up a position as mathematical instructor to the young Charles, Prince of Wales,^[14] who had come over from Jersey around July. This engagement lasted until 1648 when Charles went to Holland.

The company of the exiled royalists led Hobbes to produce an English book to set forth his theory of civil government in relation to the political crisis resulting from the war. The State, it now seemed to Hobbes, might be regarded as a great artificial man or monster (Leviathan), composed of men, with a life that might be traced from its generation under pressure of human needs to its dissolution through civil strife proceeding from human passions. The work closed with a general "Review and Conclusion", in direct response to the war, which raised the question of the subject's right to change allegiance when a former sovereign's power to protect was irrevocably lost. Hobbes also criticised religious doctrines on rationalistic grounds in the Commonwealth.

Frontispiece from De Cive (1642)

During the years of the composition of Leviathan, Hobbes remained in or near Paris. In 1647 a serious illness disabled him for six months. On recovering from this near fatal disorder, he resumed his literary task, and carried it steadily forward to completion by 1650. Meanwhile, a translation of De Cive was being produced; scholars disagree over whether Hobbes translated the work himself or not.

In 1650 a pirated edition of The Elements of Law, Natural and Politic was published. It was divided into two separate small volumes (Human Nature, or the Fundamental Elements of Policie and De corpore politico, or the Elements of Law, Moral and Politick). In 1651 the translation of De Cive was published under the title of Philosophicall Rudiments concerning Government and Society.
Meanwhile, the printing of the greater work proceeded, and finally it appeared about the middle of 1651, under the title of Leviathan, or the Matter, Forme, and Power of a Common Wealth, Ecclesiasticall and Civil, with a famous title-page engraving in which, from behind hills overlooking a landscape, there towered the body (above the waist) of a crowned giant, made up of tiny figures of human beings and bearing sword and crozier in the two hands.

The work had immediate impact. Soon Hobbes found himself more lauded and decried than any other thinker of his time. However, the first effect of its publication was to sever his link with the exiled royalists, forcing him to appeal to the revolutionary English government for protection. The exiles might very well have killed him; the secularist spirit of his book greatly angered both Anglicans and French Catholics. Hobbes fled back to England, arriving in London in the winter of 1651. Following his submission to the Council of State he was allowed to subside into private life in Fetter Lane.

Leviathan

 

Frontispiece of Leviathan

In Leviathan, Hobbes set out his doctrine of the foundation of states and legitimate governments and creating an objective science of morality. This gave rise to social contract theory. Leviathan was written during the English Civil War; much of the book is occupied with demonstrating the necessity of a strong central authority to avoid the evil of discord and civil war.

Beginning from a mechanistic understanding of human beings and the passions, Hobbes postulates what life would be like without government, a condition which he calls the state of nature; much of this was based on Hugo Grotius' works. In that state, each person would have a right, or license, to everything in the world. This, Hobbes argues, would lead to a "war of all against all" (bellum omnium contra omnes). The description contains what has been called one of the best known passages in English philosophy, which describes the natural state mankind would be in, were it not for political community: ^[15]

In such condition, there is no place for industry; because the fruit thereof is uncertain: and consequently no culture of the earth; no navigation, nor use of the commodities that may be imported by sea; no commodious building; no instruments of moving, and removing, such things as require much force; no knowledge of the face of the earth; no account of time; no arts; no letters; no society; and which is worst of all, continual fear, and danger of violent death; and the life of man, solitary, poor, nasty, brutish, and short.^[16]

In such a state, people fear death, and lack both the things necessary to commodious living, and the hope of being able to toil to obtain them. So in order to avoid it people accede to a social contract and establish a civil society. According to Hobbes, society is a population beneath a sovereign authority, to whom all individuals in that society cede some rights for the sake of protection. Any abuses of power by this authority can not be resisted because the sovereign power of the protector comes because of people surrendering their own sovereign power for protection and thereby they are the authors of all decisions made by the sovereign.^[17] "he that complaineth of injury from his sovereign complaineth that whereof he himself is the author, and therefore ought not to accuse any man but himself, no nor himself of injury because to do injury to one's self is impossible". There is no doctrine of separation of powers in Hobbes's discussion.^[18] According to Hobbes, the sovereign must control civil, military, judicial, and ecclesiastical powers.

Opposition

John Bramhall

Hobbes now turned to complete the fundamental treatise of his philosophical system. He worked so steadily that De Corpore was first printed in 1654. Also in 1654, a small treatise, Of Liberty and Necessity, was published by Bishop John Bramhall, addressed at Hobbes. Bramhall, a strong Arminian, had met and debated with Hobbes and afterwards wrote down his views and sent them privately to be answered in this form by Hobbes. Hobbes duly replied, but not for publication. But a French acquaintance took a copy of the reply and published it with "an extravagantly laudatory epistle." Bramhall countered in 1655, when he printed everything that had passed between them (under the title of A Defence of the True Liberty of Human Actions from Antecedent or Extrinsic Necessity). In 1656 Hobbes was ready with The Questions concerning Liberty, Necessity and Chance, in which he replied "with astonishing force" to the bishop. As perhaps the first clear exposition of the psychological doctrine of determinism, Hobbes's own two pieces were important in the history of the free-will controversy. The bishop returned to the charge in 1658 with Castigations of Mr Hobbes's Animadversions, and also included a bulky appendix entitled The Catching of Leviathan the Great Whale.

John Wallis

Hobbes opposed the existing academic arrangements, and assailed the system of the original universities in "Leviathan". He went on to publish "De Corpore", which contained not only tendentious views on mathematics, but also an unacceptable proof of the squaring of the circle. This all led mathematicians to target him for polemics and sparked John Wallis to become one of his most persistent opponents. From 1655, the publishing date of "De Corpore", Hobbes and Wallis went round after round trying to disprove each other's positions. After years of debate, the spat over proving the squaring of the circle gained such notoriety that this feud has become one of the most infamous in mathematical history.

Atheism

Hobbes has been accused of atheism, or (in the case of Bramhall) of teachings which could lead to atheism. This was an important accusation, and Hobbes himself wrote, in his answer to Bramhall's "the catching of the Leviathan" that "atheism, impiety, and the like are words of the greatest defamation possible".^[19] Hobbes always defended himself from such accusations.^[20] In more recent times also, much has been made of his religious views by scholars such as Richard Tuck and J. G. A. Pocock, but there is still widespread disagreement about the exact significance of Hobbes's unusual views on religion.

As Martinich (1995, p. 31) has pointed out, in Hobbes's time, the term "atheist" was frequently applied to people who believed in God, but not divine providence, or to people who believed in God, but also maintained other beliefs which were inconsistent with such belief. He says that this "sort of discrepancy has led to many errors in determining who was an atheist in the early modern period". In this extended early modern sense of atheism, Hobbes did indeed take positions which were in strong disagreement with church teachings of his time. For example, Hobbes argued repeatedly that there are no incorporeal substances, and that all things, including human thoughts, and even God, heaven, and hell are corporeal, matter in motion. He argued that "though Scripture acknowledge spirits, yet doth it nowhere say, that they are incorporeal, meaning thereby without dimensions and quantity".^[21] (In this view, Hobbes claimed to be following Tertullian, whose views were not condemned in the First Council of Nicaea.) He also, like Locke, stated that true revelation can never be in disagreement with human reason and experience,^[22] although he also argues that people should accept revelation and its interpretations also for the reason that they should accept the commands of their sovereign, in order to avoid war.

Later life

In 1658, Hobbes published the final section of his philosophical system, completing the scheme he had planned more than twenty years before. De Homine consisted for the most part of an elaborate theory of vision. The remainder of the treatise dealt cursorily with some of the topics more fully treated in the Human Nature and the Leviathan. In addition to publishing some controversial writings on mathematics and physics, Hobbes also continued to produce philosophical works. From the time of the Restoration he acquired a new prominence; "Hobbism" became a byword for all that respectable society ought to denounce. The young king, Hobbes' former pupil, now Charles II, remembered Hobbes and called him to the court to grant him a pension of £100.

The king was important in protecting Hobbes when, in 1666, the House of Commons introduced a bill against atheism and profaneness. That same year, on 17 October 1666, it was ordered that the committee to which the bill was referred "should be empowered to receive information touching such books as tend to atheism, blasphemy and profaneness... in particular... the book of Mr. Hobbes called the Leviathan".^[23] Hobbes was terrified at the prospect of being labelled a heretic, and proceeded to burn some of his compromising papers. At the same time, he examined the actual state of the law of heresy. The results of his investigation were first announced in three short Dialogues added as an Appendix to his Latin translation of Leviathan, published at Amsterdam in 1668. In this appendix, Hobbes aimed to show that, since the High Court of Commission had been put down, there remained no court of heresy at all to which he was amenable, and that nothing could be heresy except opposing the Nicene Creed, which, he maintained, Leviathan did not do.

The only consequence that came of the bill was that Hobbes could never thereafter publish anything in England on subjects relating to human conduct. The 1668 edition of his works was printed in Amsterdam because he could not obtain the censor's licence for its publication in England. Other writings were not made public until after his death, including Behemoth: the History of the Causes of the Civil Wars of England and of the Counsels and Artifices by which they were carried on from the year 1640 to the year 1662. For some time, Hobbes was not even allowed to respond, whatever his enemies tried. Despite this, his reputation abroad was formidable, and noble or learned foreigners who came to England never forgot to pay their respects to the old philosopher.

His final works were a curious mixture: an autobiography in Latin verse in 1672, and a translation of four books of the Odyssey into "rugged" English rhymes that in 1673 led to a complete translation of both Iliad and Odyssey in 1675.

In October 1679, Hobbes suffered a bladder disorder, which was followed by a paralytic stroke from which he died on 4 December 1679. He is said to have uttered the last words "A great leap in the dark" in his final moments of life.^[24] He was interred within St. John the Baptist Church in Ault Hucknall in Derbyshire, England.

Works

• 1602. Latin translation of Euripides' Medea (lost).
• 1620. Three of the discourses in the Horae Subsecivae: Observation and Discourses (A Discourse of Tacitus, A Discourse of Rome, and A Discourse of Laws).^[13]
• 1626. De Mirabilis Pecci, Being the Wonders of the Peak in Darby-shire, (a poem first published in 1636)
• 1629. Eight Books of the Peloponnesian Warre, translation with an Introduction of Thucydides's History of the Peloponnesian War
• 1630. A Short Tract on First Principles, British Museum, Harleian MS 6796, ff. 297–308: critical edition with commentary and French translation by Jean Bernhardt: Court traité des premiers principes, Paris, PUF, 1988 (authorship doubtful: this work is attributed by some critics to Robert Payne).^[25]
• 1637 A Briefe of the Art of Rhetorique (in Molesworth's edition the title is The Whole Art of Rhetoric)
• 1639. Tractatus opticus II, (British Library, Harley MS 6796, ff. 193–266) ^[26]
• 1640. Elements of Law, Natural and Politic (circulated only in handwritten copies, first printed edition, without Hobbes's permission in 1650)
• 1641. Objectiones ad Cartesii Meditationes de Prima Philosophia (Third series of Objections)
• 1642. De Cive (Latin. first limited edition)
• 1643. De Motu, Loco et Tempore (first edition 1973 with the title: Thomas White's De Mundo Examined)
• 1644. Part of the Praefatio to Mersenni Ballistica (in F. Marini Mersenni minimi Cogitata physico-mathematica. In quibus tam naturae quàm artis effectus admirandi certissimis demonstrationibus explicantur)
• 1644. Opticae, liber septimus, (written in 1640) in Universae geometriae mixtaeque mathematicae synopsis, edited by Marin Mersenne (reprinted by Molesworth in OL V pp. 215–248 with the title Tractatus Opticus)
• 1646. A Minute or First Draught of the Optiques (Harley MS 3360; Molesworth published only the dedication to Cavendish and the conclusion in EW VII, pp. 467–471)
• 1646. Of Liberty and Necessity (published without the permission of Hobbes in 1654)
• 1647. Elementorum Philosophiae Sectio Tertia De Cive (second expanded edition with a new Preface to the Reader)
• 1650. Answer to Sir William Davenant's Preface before Gondibert
• 1650. Human Nature: or The fundamental Elements of Policie (first thirteen chapters of The Elements of Law, Natural and Politic, published without Hobbes's authorization)
• 1650. Pirated Edition of The Elements of Law, Natural and Politic, repackaged to include two parts:
  • Human Nature, or the Fundamental Elements of Policie (chapters 14–19 of Part One of the Elements of 1640)
  • De Corpore Politico (Part Two of the Elements of 1640)
• 1651. Philosophical Rudiments concerning Government and Society (English translation of De Cive)^[27]
• 1651. Leviathan, or the Matter, Forme, and Power of a Commonwealth, Ecclesiasticall and Civil
• 1654. Of Libertie and Necessitie, a Treatise
• 1655. De Corpore (Latin)
• 1656. Elements of Philosophy, The First Section, Concerning Body (anonymous English translation of De Corpore)
• 1656. Six Lessons to the Professor of Mathematics
• 1656. The Questions concerning Liberty, Necessity and Chance (reprint of Of Libertie and Necessitie, a Treatise, with the addition of Bramhall's reply and Hobbes's reply to Bramahall's reply)
• 1657. Stigmai, or Marks of the Absurd Geometry, Rural Language, Scottish Church Politics, and Barbarisms of John Wallis
• 1658. Elementorum Philosophiae Sectio Secunda De Homine
• 1660. Examinatio et emendatio mathematicae hodiernae qualis explicatur in libris Johannis Wallisii
• 1661. Dialogus physicus, sive De natura aeris
• 1662. Problematica Physica (translated in English in 1682 as Seven Philosophical Problems)
• 1662. Seven Philosophical Problems, and Two Propositions of Geometru (published posthumously)
• 1662. Mr. Hobbes Considered in his Loyalty, Religion, Reputation, and Manners. By way of Letter to Dr. Wallis (English autobiography)
• 1666. De Principis & Ratiocinatione Geometrarum
• 1666. A Dialogue between a Philosopher and a Student of the Common Laws of England (published in 1681)
• 1668. Leviathan (Latin translation)
• 1668. An Answer to a Book published by Dr. Bramhall (published in 1682)
• 1671. Three Papers Presented to the Royal Society Against Dr. Wallis. Together with Considerations on Dr. Walllis his Answer to them
• 1671. Rosetum Geometricum, sive Propositiones Aliquot Frustra antehac tentatae. Cum Censura brevi Doctrinae Wallisianae de Motu
• 1672. Lux Mathematica. Excussa Collisionibus Johannis Wallisii
• 1673. English translation of Homer's Iliad and Odyssey
• 1674. Principia et Problemata Aliquot Geometrica Antè Desperata, Nunc breviter Explicata & Demonstrata
• 1678. Decameron Physiologicum: Or, Ten Dialogues of Natural Philosophy
• 1679. Thomae Hobbessii Malmesburiensis Vita. Authore seipso (Latin autobiography, translated in English in 1680)
• 1680. An Historical Narration concerning Heresie, And the Punishment thereof
• 1681. Behemoth, or The Long Parliament (written in 1668, unpublished at the request of the King, first pirated edition 1679)
• 1682. Seven Philosophical Problems (English translation of Problematica Physica, 1662)
• 1682. A Garden of Geometrical Roses (English translation of Rosetum Geometricum, 1671)
• 1682. Some Principles and Problems in Geometry (English translation of Principia et Problemata, 1674)
• 1688. Historia Ecclesiastica Carmine Elegiaco Concinnata

Falcon Heavy

From Wikipedia, the free encyclopedia

   

Falcon Heavy

Drawing of the Falcon Heavy reusable (left) and expendable (right) configurations
Function	Orbital launch vehicle and potential Lunar launch vehicle[1]
Manufacturer	SpaceX
Country of origin	United States
Cost per launch (2014)	$85M for up to 6,400 kg to GTO
Size
Height	68.4 m (224 ft)
Diameter	3.66 m (12.0 ft)
Mass	1,462,836 kg (3,225,001 lb)
Stages	2+
Capacity
Payload to LEO	53,000 kg (117,000 lb)
Payload to GTO	21,200 kg (46,700 lb)
Launch history
Status	In Development
Launch sites	KSC LC-39A Vandenberg SLC-4E[2]
Total launches	0
Successes	0
Failures	0
First flight	2015 (projected)
Boosters (Stage 0)
No. boosters	2
Engines	9 Merlin 1D
Thrust	5,880 kN (1,323,000 lbf)(sl)
Total thrust	17,615 kN (3,960,000 lbf) (total sea-level thrust of boosters plus core)[3]
Specific impulse	Sea level: 282 sec Vacuum: 311 sec
Burn time	Unknown
Fuel	LOX/RP-1
First stage
Engines	9 Merlin 1D
Thrust	5,880 kN (1,323,000 lbf)(sl)
Specific impulse	Sea level: 282 sec Vacuum: 311 sec
Burn time
Fuel	LOX/RP-1
Second stage
Engines	1 Merlin 1D Vacuum
Thrust	801 kN (180,000 lbf)
Specific impulse	Vacuum: 342 sec [4]
Burn time	375 seconds[5]
Fuel	LOX/RP-1

Falcon Heavy (FH), previously known as the Falcon 9 Heavy, is a spaceflight launch system being designed and manufactured by SpaceX. The Falcon Heavy is a variant of the Falcon 9 v1.1 launch vehicle and will consist of a standard Falcon 9 rocket core, with two additional Falcon 9 first stages as strap-on boosters^[6] – this will increase the low Earth orbit (LEO) payload to about 53 tonnes, compared to about 13 tonnes for a Falcon 9. The first launch is expected in 2015.^[7]

Design

From left to right, Falcon 1, Falcon 9 v1.0, three versions of Falcon 9 v1.1, and two versions of the Falcon Heavy

The Falcon Heavy configuration consists of a standard Falcon 9 with two additional Falcon 9 first stages acting as liquid strap-on boosters,^[6] which is conceptually similar to EELV Delta IV Heavy launcher and proposals for the Atlas V HLV and Russian Angara. Falcon Heavy will be more capable than any other operational rocket, with a payload to low earth orbit of 53,000 kilograms (117,000 lb).^[10] The rocket was designed to meet or exceed all current requirements of human rating. The structural safety margins are 40% above flight loads, higher than the 25% margins of other rockets.^[20]

The Falcon Heavy's designed payload capacity, capabilities, and total thrust are equivalent to the Saturn C-3 launch vehicle concept (1960) for the Earth Orbit Rendezvous approach to an American lunar landing.^[21]

First stage

The first stage is powered by three Falcon 9 derived cores, each equipped with 9 Merlin 1D engines. The Merlin 1D is an updated version of the previous Merlin 1C engine and provides a sea level thrust of 620 kN (140,000 lbf) at a specific impulse of 282 seconds,^[22] a vacuum thrust of 690 kN (155,000 lbf) at 311 seconds,^[22] and is throttleable from 100% to 70%.^[23]

The Falcon Heavy has a total sea-level thrust at liftoff of 17,615 kN (3,960,000 lb_f), from the 27 Merlin 1D engines, while thrust rises to 20,000 kilonewtons (4,500,000 lbf) as the craft climbs out of the atmosphere.^[5] Falcon Heavy has been designed with a unique propellant crossfeed capability, where some of the center core engines are supplied with fuel and oxidizer from the two side cores, up until the side cores are near empty and ready for the first separation event.^[24] This allows engines from all three cores to ignite at launch and operate at full thrust until booster depletion, while still leaving the central core with most of its propellant at booster separation.^[25]

After the side cores are released, the center engine in each side core will continue to burn for a few seconds in order to control the trajectory of the side booster.^[26][27]

All three cores of the Falcon Heavy arrange the engines in a structural form SpaceX calls Octaweb, aimed at streamlining the manufacturing process,^[28] and each core will include four extensible landing legs,^[27] which are intended to be used for vertical-landing once the post-mission technology development effort is completed.^[29]

Second stage

The upper stage is powered by a single Merlin 1D engine modified for vacuum operation, with an expansion ratio of 117:1 and a nominal burn time of 345 seconds. For added reliability of restart, the engine has dual redundant pyrophoric igniters (TEA-TEB).^[6]

The interstage, which connects the upper and lower stage for Falcon 9, is a carbon fiber aluminum core composite structure. Stage separation occurs via reusable separation collets and a pneumatic pusher system. The Falcon 9 tank walls and domes are made from aluminum lithium alloy. SpaceX uses an all-friction stir welded tank. The second stage tank of Falcon 9 is simply a shorter version of the first stage tank and uses most of the same tooling, material and manufacturing techniques. This approach reduces manufacturing costs during vehicle production.^[6]

Reusable technology development

Although not a part of the initial Falcon Heavy design, SpaceX is doing parallel development on a reusable rocket launching system that is intended to be extensible to the Falcon Heavy, first to the booster stage and ultimately to the second stage as well.

Early on, SpaceX had expressed hopes that both rocket stages would eventually be reusable.^[30] More recently, in 2011, SpaceX announced a funded development program to build and fly a reusable launch system that will ultimately bring a first stage back to the launch site in minutes — and a second stage back to the launch pad, following orbital realignment with the launch site and atmospheric reentry, in up to 24 hours — with both stages designed to be available for reuse within "single-digit hours" after return.^[31] As of February 2012^[update], design is complete on the system for "bringing the rocket back to launchpad using only thrusters."^[31]

The reusable launch system technology is under consideration for both the Falcon 9 and the Falcon Heavy. It is particularly well suited to the Falcon Heavy where the two outer cores separate from the rocket much earlier in the flight profile, and are therefore both moving at a slower velocity at the initial separation event.^[31]

As of March 2013^[update], the publicly announced aspects of the SpaceX reusable rocket technology development effort include an active test campaign of the low-altitude, low-speed Grasshopper vertical takeoff, vertical landing (VTVL) technology demonstrator rocket,^[32][33] and a high-altitude, high-speed Falcon 9 post-mission booster-return test campaign where—beginning in late-2013, with the sixth overall flight of Falcon 9—every Falcon 9 first stage which was instrumented and equipped as a controlled descent test vehicle to accomplish propulsive-return over-water tests.^[29]
SpaceX has indicated that the Falcon Heavy payload performance to Geosynchronous transfer orbit (GTO) will be reduced by addition of the reusable technology, but would fly at much lower launch price. With full reusability on all three booster cores, GTO payload will be 7,000 kg (15,000 lb). If only the two outside cores fly as reusable cores while the center core is expendable, GTO payload would be approximately 14,000 kg (31,000 lb).^[34] "Falcon 9 will do satellites up to roughly 3.5 tonnes, with full reusability of the boost stage, and Falcon Heavy will do satellites up to 7 tonnes with full reusability of the all three boost stages," [Musk] said, referring to the three Falcon 9 booster cores that will comprise the Falcon Heavy's first stage. He also said Falcon Heavy could double its payload performance to GTO "if, for example, we went expendable on the center core."

Pricing and development funding

At an appearance in May 2004 before the U.S. Senate Committee on Commerce, Science and Transportation, Elon Musk testified, "Long term plans call for development of a heavy lift product and even a super-heavy, if there is customer demand. We expect that each size increase would result in a meaningful decrease in cost per pound to orbit. ... Ultimately, I believe $500 per pound or less is very achievable."^[35] This $500 per pound goal stated by Musk in 2011 is 35 percent of the cost of the lowest-cost-per-pound LEO-capable launch system in a circa-2000 study, referenced by spaceref.com in 2001, the Zenit, a medium-lift launch vehicle that can carry 14,000 kilograms (30,000 lb) into LEO.^[36]

As of March 2013^[update], Falcon Heavy launch prices are below $1,000 per pound ($2,200/kg) to low-Earth orbit when the launch vehicle is transporting its maximum delivered cargo weight.^[37] The published prices for Falcon Heavy launches have moved some from year to year, with announced prices for the various versions of Falcon Heavy priced at US$80-125 million in 2011,^[13] US$83-128 million in 2012,^[14] US$77.1-135 million in 2013,^[38] and US$85 million for up to 6,400 kg to GTO (with no published price for heavier GTO or any LEO payload) in 2014.^[39] Launch contracts typically reflect launch prices at the time the contract is signed.

SpaceX has claimed the cost of reaching low Earth orbit can be as low as US$1,000/lb if an annual rate of four launches can be sustained, and as of 2011 planned to eventually launch 10 Falcon Heavy and 10 Falcon 9 annually.^[9] A third launch site, intended exclusively for SpaceX private use, is planned, with locations in Texas, Florida, and Georgia under consideration.^[40] A site near Brownsville, Texas was the front runner as of April 2013^[update]. SpaceX expects to start construction on the third Falcon Heavy launch facility, after final site selection, no earlier than 2014, with the first launches from the facility no earlier than 2016.^[40] In late 2013, SpaceX had projected Falcon Heavy's inaugural flight to be sometime in 2014,^[5] but as of March 2014^[update] expects the first launch to be in 2015^[41] due to limited manufacturing capacity and the need to deliver on the Falcon 9 launch manifest.^[7]
The Falcon Heavy is being developed with private capital. No government financing is being provided for its development.^[42]

SpaceX current prices for space launch are already the lowest in the industry.^[43] If SpaceX is able to successfully complete development on its SpaceX reusable rocket technology and return booster stages to the launch pad for reuse, a new economically-driven Space Age could result.^[42][44]

Testing

A new, partially underground test stand is being built at the SpaceX Rocket Development and Test Facility in McGregor, Texas specifically to test the triple cores and twenty seven rocket engines of the Falcon Heavy.^[45]

Launches and potential payloads

Flight Number	Date & Time (GMT)	Payload	Customer	Outcome	Remarks
1	2015[46][47]	Falcon Heavy Demo Flight 1	SpaceX	Scheduled	Hardware is expected to arrive at the Vandenberg AFB in 2014[46]
2	2015[46]	Falcon Heavy Demo Flight 2 called: STP-2[48] Payload: GPIM[49][50][51]	DoD	Scheduled	The mission will support the U.S. Air Force EELV certification process for the Falcon Heavy.[47]
3	2017[47]	Communications satellite[52]	Intelsat[53]	Scheduled	First Commercial mission for Falcon Heavy.[53] First launch to a Geostationary transfer orbit for Falcon Heavy.[52]

'Red Dragon' Mars Mission[edit]

Main article: Red Dragon (spacecraft)

In 2011, NASA Ames Research Center developed a proposal for a low-cost Mars mission that would use Falcon Heavy as the launch vehicle and trans-Martian injection vehicle, and the Dragon capsule to enter the Martian atmosphere. The science objectives of the mission would be to look for evidence of life — detecting "molecules that are proof of life, like DNA or perchlorate reductase ... proof of life through biomolecules. ... Red Dragon would drill 3.3 feet (1.0 m) or so underground, in an effort to sample reservoirs of water ice known to lurk under the red dirt." The mission cost as of 2011 was projected to be less than US$425,000,000, not including the launch cost.^[54] The concept was to be formally proposed in 2012/2013 as a NASA Discovery mission but has not been selected for funding.^[55]

First commercial contract: Intelsat

In May 2012, SpaceX announced that Intelsat had signed the first commercial contract for a Falcon Heavy flight. It was not confirmed when the first Intelsat launch would occur, but the agreement will have SpaceX delivering satellites to geosynchronous transfer orbit.^[52][53]

First DoD contract: USAF

In December 2012, SpaceX announced its first Falcon Heavy launch contract with the United States Department of Defense (DoD). "The United States Air Force Space and Missile Systems Center awarded SpaceX two Evolved Expendable Launch Vehicle (EELV)-class missions" including the Space Test Program 2 (STP-2) mission for Falcon Heavy, initially scheduled to be launched in 2015.^[48][56]

Space Launch System

From Wikipedia, the free encyclopedia

 

Space Launch System

Artist's rendering of the SLS Block 1 crewed variant launching
Function	Launch vehicle
Country of origin	United States
Cost per launch ()	US$500 million (2012)[1]
Size
Diameter	8.4 m (330 in) (core stage)
Stages	2
Capacity
Payload to LEO	70,000 to 130,000 kg (150,000 to 290,000 lb)
Associated rockets
Family	Shuttle-Derived Launch Vehicles
Launch history
Status	Undergoing development
Launch sites	LC-39, Kennedy Space Center
First flight	December 17, 2017[2]
Notable payloads	Orion MPCV
Boosters (Block I)
No boosters	2 Space Shuttle Solid Rocket Boosters (5-segment)
Engines	1
Thrust	16,000 kN (3,600,000 lbf)
Total thrust	32,000 kN (7,200,000 lbf)
Specific impulse	269 seconds (2.64 km/s)
Burn time	124 seconds
Fuel	APCP
First Stage (Block I, IB, II) - Core Stage
Diameter	8.4 m (330 in)
Empty mass	85,270 kg (187,990 lb)
Gross mass	979,452 kg (2,159,322 lb)
Engines	4 RS-25D/E[3]
Thrust	7,440 kN (1,670,000 lbf)
Specific impulse	363 seconds (3.56 km/s) (sea level), 452 seconds (4.43 km/s) (vacuum)
Fuel	LH2/LOX
Second Stage (Block I) - ICPS
Length	13.7 m (540 in)
Diameter	5 m (200 in)
Empty mass	3,490 kg (7,690 lb)
Gross mass	30,710 kg (67,700 lb)
Engines	1 RL10B-2
Thrust	110.1 kN (24,800 lbf)
Specific impulse	462 seconds (4.53 km/s)
Burn time	1125 seconds
Fuel	LH2/LOX
Second Stage (Block IB, Block II) - Exploration Upper Stage
Engines	4 RL10
Thrust	440 kN (99,000 lbf)
Fuel	LH2/LOX

The Space Launch System (SLS) is a United States Space Shuttle-derived heavy launch vehicle being designed by NASA. It follows the cancellation of the Constellation Program, and is to replace the retired Space Shuttle. The NASA Authorization Act of 2010 envisions the transformation of the Ares I and Ares V vehicle designs into a single launch vehicle usable for both crew and cargo.
The SLS launch vehicle is to be upgraded over time with more powerful versions. Its initial Block I version, without an upper stage, is to lift a payload of 70 metric tons to low Earth orbit (LEO) and the Block IB approximately 105 metric tons.^[4] The SLS Block II with an Exploration Upper Stage and advanced boosters is planned to have a payload lift capability of around 155 metric tons to LEO,^[5] above the congressionally mandated minimum of 130 metric tons;^[6] this would make the SLS the most capable heavy lift vehicle ever built.^[7]

SLS is to be capable of lifting astronauts and hardware to near-Earth destinations such as asteroids, the Moon, Mars, and most of the Earth's Lagrangian points. SLS may also support trips to the International Space Station, if necessary. The SLS program is integrated with NASA's Orion Crew and Service Module, with astronauts returning to earth in a capsule-shaped, four-person crew module. SLS will use the ground operations and launch facilities at NASA's Kennedy Space Center, Florida. The first flight-test of the Block I variant of the vehicle, Exploration Mission 1, is scheduled to fly in 2017.

Design and development

Space Launch System's planned variants

On September 14, 2011, NASA announced its design selection for the new launch system, declaring that it would take the agency's astronauts farther into space than ever before and provide the cornerstone for future US human space exploration efforts.^[8][9][10] Four versions of the launch vehicle have been planned at various times – Blocks 0, I, IA, IB and II. Each configuration utilizes different core stages, boosters and upper stages, with some components deriving directly from Space Shuttle hardware and others being developed specifically for the SLS.^[11] Block II of the SLS, the most capable variant, was initially depicted as having five RS-25E engines, upgraded boosters and an 8.4-meter diameter upper stage with three J-2X engines.^[12][13] Along with its baseline 8.4 meter diameter payload fairing a longer but thinner 5-meter class payload fairing with a length of 10 m or greater is also considered for propelling heavier payloads to deep space.^[14] Since then a number of changes have been made, with Block 0 and Block IA no longer in design and the final Block II design being dependent on an ongoing booster competition and further analysis. The initial Block I two-stage variant will have a lift capability of between 70,000 and 77,000 kg, while the proposed Block II final variant will have similar lift capacity and height to the original Saturn V.^[15] By November 2011, NASA had selected five rocket configurations for wind tunnel testing, described in three Low Earth Orbit classes; 70 metric tons (t), 95 t, and 140 t.^[16]

In 2011, NASA announced that development of the Orion spacecraft from the Constellation program will continue as the Multi-Purpose Crew Vehicle (MPCV)^[17] to be flown on SLS.

On July 31, 2013 the SLS passed the Preliminary Design Review (PDR). The review encompassed all aspects of the SLS' design, not only the rocket and boosters but also ground support and logistical arrangements. Successful completion of the PDR paves the way for Gate-C approval by NASA senior administration, enabling the project to move from design to implementation.^[18]

Core stage

The core stage of the SLS is common to all vehicle configurations, essentially consisting of a modified Space Shuttle External Tank with the aft section adapted to accept the rocket's Main Propulsion System (MPS) and the top converted to host an interstage structure.^[7][19] It will be fabricated at the Michoud Assembly Facility.^[20] The stage will utilize four RS-25 engines.

• Block 0 was an initial planning baseline version, from Shuttle components, using an 8.4 meter core stage and three RS-25D engines.^[21][22] However, NASA managers preferred designing the SLS core stage to use four RS-25 engines, skipping to the Block 0 configuration, as it would remove the need to substantially redesign the core stage to accommodate an extra engine.^[23]
• Block I and IB: 8.4 meter core with four RS-25D/E engines.^[11]
• Block II: Initially planned to use five RS-25D/E engines,^[12] Block II is now expected to use four engines like Block I and IB.^[3]

Boosters

In addition to the thrust produced by the engines on the core stage, the first two minutes of flight will be aided by two rocket boosters mounted to either side of the core stage.

Shuttle-derived solid rocket boosters

Blocks I and IB of the SLS will use modified Space Shuttle Solid Rocket Boosters (SRBs), extended from four segments to five segments. Unlike the Space Shuttle boosters, these will not be recovered and will sink into the Atlantic Ocean downrange.^[2] Alliant Techsystems (ATK), the builder of the Space Shuttle SRBs, has completed three full-scale, full-duration static tests of the five-segment rocket booster. Development motor (DM-1) was successfully tested on September 10, 2009; DM-2 on August 31, 2010 and DM-3 on September 8, 2011. For DM-2 the motor was cooled to a core temperature of 40 degrees Fahrenheit (4 degrees Celsius), and for DM-3 it was heated to above 90 °F (32 °C). In addition to other objectives, these tests validated motor performance at extreme temperatures.^[24][25][26] Each five-segment SRB has a thrust of 3,600,000 lbf (16 MN) at sea level.

Advanced boosters

NASA will eventually switch from Shuttle-derived five-segment SRBs to upgraded boosters^[27] These may be of either the solid rocket or liquid rocket booster type.^[11] NASA originally planned to incorporate these advanced boosters in the Block IA configuration of SLS, but this was superseded by Block IB, which will continue to use five-segment SRBs combined with a new upper stage,^[28] after it was determined that the Block IA configuration would result in high acceleration which would be unsuitable for Orion and could result in a costly redesign of the Block I core.^[29] Prior to the selection of Block IB, NASA intended to begin the Advanced Booster Competition,^[3][30][31] which would have selected an advanced booster in 2015. Though NASA is no longer planning on selecting new boosters for the first flights of SLS,^[32] competitors for the advanced booster include:

• Aerojet, in partnership with Teledyne Brown, with a domestic version of an uprated Soviet NK-33 LOX/RP-1 engine, an engine derived from the NK-15 initially designed to lift the unsuccessful N-1 Soviet moonshot vehicle, with each engine's thrust increased from 394,000 lbf (1.75 MN) to at least 500,000 lbf (2.2 MN) at sea level. This booster would be powered by eight AJ-26-500 engines,^[33] or four AJ-1E6 engines^[34] On February 14, 2013, NASA awarded a $23.3 million 30-month contract Aerojet to build a full-scale 550,000-pound thrust class main injector and thrust chamber to be used in the advanced booster.^[35] Two standard Aerojet AJ-26 engines, together producing a combined 735,000 lbf (3.27 MN) of sea level thrust, successfully lifted the Antares rocket in 2013.^[36]
• Pratt & Whitney Rocketdyne and Dynetics, with a booster design known as "Pyrios", which would use two F-1B engines derived from the F-1 LOX/RP-1 engine that powered the first stage of the Saturn V vehicle in the Apollo program. In 2012, it was determined that if the dual-engined Pyrios booster was selected for the SLS Block II, the payload could be 150 metric tons (t) to Low Earth Orbit, 20 t more than the baseline 130 t to LEO for SLS Block II.^[37] In 2013, it was reported that in comparison to the F-1 engine that it is derived from, the F-1B engine is to have improved efficiency, be more cost effective and have fewer engine parts.^[38] Each F-1B is to produce 1,800,000 lbf (8.0 MN) of thrust at sea level, an increase over the 1,550,000 lbf (6.9 MN) of thrust of the initial F-1 engine.^[39]
• ATK proposed an advanced SRB named "Dark Knight" with more energetic propellant, a lighter composite case, and other design improvements to reduce costs and improve performance. ATK states it provides "capability for the SLS to achieve 130 t payload with significant margin" when combined with a Block II core stage containing five RS-25 engines. However, the advanced SRB would achieve no more than 113 t to low earth orbit with the current core stage with four RS-25 engines.^[3][37][40]

Christopher Crumbly, manager of NASA’s SLS advanced development office in January 2013 commented on the booster competition, "The F-1 has great advantages because it is a gas generator and has a very simple cycle. The oxygen-rich staged combustion cycle [Aerojet’s engine] has great advantages because it has a higher specific impulse. The Russians have been flying ox[ygen]-rich for a long time. Either one can work. The solids [of ATK] can work."^[41]

Upper stage

An RL10 engine, like the one pictured above, will be used as the second stage engine in both the ICPS and EUS upper stages.

SLS will make use of two upper stages, the Interim Cryogenic Propulsion Stage and the Exploration Upper Stage both powered by RL10 engines.

Confirmed upper stages

• Block I, scheduled to fly only Exploration Mission 1 (EM-1) in 2017, will use a modified Delta IV 5 meter Delta Cryogenic Second Stage (DCSS),^[42] referred to as the Interim Cryogenic Propulsion Stage (ICPS). This stage will be powered a single RL10B-2. SLS will be capable of lifting 70 metric tons in this configuration, however the ICPS will be considered part of the payload and be placed into an initial 1,800 km by -93 km suborbital trajectory along with the Orion crew capsule, where the the stage will perform an orbital insertion burn and then a translunar injection burn to send the uncrewed Orion on a circumlunar excursion.^[43]

• Block IB, scheduled to debut on Exploration Mission 2 (EM-2), will use the 8.4 meter Exploration Upper Stage (EUS), previously named the Dual Use Upper Stage (DUUS), powered by four RL10 engines.^[28] The EUS is to complete the SLS ascent phase and then re-ignite to send its payload to destinations beyond low Earth orbit, similar to the role performed by the Saturn V's 3rd stage, the J-2 powered S-IVB, in function but closer to the Saturn I's 2nd stage, the S-IV, in engine layout as the S-IV contained a cluster of six RL-10 engines. The SLS's four RL-10 engined 2nd stage will be capable of placing 105^[29] to 118^[5] metric tons into low Earth orbit.

• Block II, not expected until the 2030s,^[29] would combine the Block IB EUS with advanced boosters and be capable of placing 155 metric tons into LEO.^[5] Previously, NASA had focused development on an Earth Departure Stage powered by two or three J-2X engines,^[44][45] which has been dropped in favor of the RL10 powered EUS.^[28]

Other upper stages

Prior to the selection of the EUS, NASA and Boeing analyzed the performance of several upper stage options:^[46]

• Block I SLS without an upper stage would be capable of delivering 70 t to low earth orbit (LEO), and, using an ICPS, 20.2 t to Trans-Mars injection (TMI) and 2.9 t to Europa.
• A 4 engine RL10 option, could deliver 93.1 t to LEO, 31.7 t to TMI and 8.1 t to Europa.
• A 2 engine MB60 (an comparable to the RL60)^[47] could deliver 97 t to LEO, 32.6 t to TMI and 8.5 t to Europa.
• A single engine J-2X, with its higher thrust than other upper stage options, could deliver 105.2 t to LEO but due to lower specific impulse than the RL10 or MB60 its long range capability would be marginally lower than the previous two options: 31.6 t to TMI and 7.1 to Europa.

An additional beyond LEO engine for interplanetary travel from Earth orbit to Mars orbit, and back, is being studied at Marshall Space Flight Center with a focus on nuclear thermal rocket (NTR) engines, which would be at least twice as efficient as chemical rockets. NTR engines, such as the Pewee of Project Rover, were selected in the Mars Design Reference Architecture (DRA).^[48][49][50]
An NTR equipped Mars transfer vehicle would cut down on trip times and therefore reduce the amount of time the crew would be exposed to the most penetrating cosmic rays. Over $1.5 billion has been invested over the years in the development and successful ground testing of NTR technology during Project Rover and related projects.^[51]

Assembled rocket

Before launch, the SLS will have the ability to tolerate a minimum of 13 tanking cycles due to launch scrubs and other launch delays. The assembled rocket is to be able to remain at the launch pad for a minimum of 180 days and can remain in stacked configuration for at least 200 days without destacking.^[52]

Program costs

During the joint Senate-NASA presentation in September 2011, it was stated that the SLS program has a projected development cost of $18 billion through 2017, with $10 billion for the SLS rocket, $6 billion for the Orion Multi-Purpose Crew Vehicle and $2 billion for upgrades to the launch pad and other facilities at Kennedy Space Center.^[53] These costs and schedule are considered optimistic in an independent 2011 cost assessment report by Booz Allen Hamilton for NASA.^[54] An unofficial 2011 NASA document estimated the cost of the program through 2025 to total at least $41bn for four 70 t launches (1 unmanned in 2017, 3 manned starting in 2021),^[55] with the 130 t version ready no earlier than 2030.^[56] HEFT estimated unit costs for Block 0 at $1.6bn and Block 1 at $1.86bn in 2010.^[57]
However since these estimates were made the Block 0 was dropped in late 2011 and is no longer being designed,^[23] and NASA announced in 2013 that the European Space Agency will build the Orion Service Module.^[58]

NASA SLS deputy project manager Jody Singer at Marshall Space Flight Center, Huntsville, Alabama stated in September 2012 that $500 million per launch is a reasonable target cost for SLS, with a relatively minor dependence of costs on launch capability.^[1] By comparison, the cost for a Saturn V launch was US$185 million in 1969 dollars.^[59]

On July 24, 2014, Government Accountability Office audit predicted that SLS will not launch by the end of 2017 as planned since NASA is not receiving sufficient funding.^[60]

Criticism

Criticism of SLS falls in several areas. The Space Access Society, Space Frontier Foundation and the Planetary Society called for cancellation of the project, arguing that SLS will consume the funds for other projects from the NASA budget and will not reduce launch costs;^[61][62][63] some estimate this cost for the SLS to be about $8,500 per pound lifted to low earth orbit (LEO).^{[64][better source needed]} U.S. Representative Dana Rohrabacher and others added that instead, a propellant depot should be developed and the Commercial Crew Development program accelerated.^{[61][65][66][67][68]} Two studies, one not publicly released from NASA^[69][70] and another from the Georgia Institute of Technology, show this option to be a possibly cheaper alternative.^[71][72]

Others suggest it will cost less to use an existing lower payload capacity rocket (Atlas V, Delta IV, Falcon 9, or the derivative Falcon Heavy), with on-orbit assembly and propellant depots as needed, rather than develop a new launch vehicle for space exploration without competition for the whole design.^{[73][74][75][76][77]} The Augustine commission proposed an option for a commercial 75 metric ton launcher with lower operating costs, and noted that a 40 to 60 t launcher can support lunar exploration.^[78]

Mars Society founder Robert Zubrin who co-authored the influential Mars Direct concept suggested that a heavy lift vehicle should be developed for $5 billion on fixed-price requests for proposal. Zubrin also disagrees with those that say the U.S. does not need a heavy-lift vehicle.^[79] Based upon extrapolations of increased payload lift capabilities from past experience with SpaceX's Falcon launch vehicles, SpaceX CEO Elon Musk guaranteed that his company could build the conceptual Falcon XX, a vehicle in the 140-150 t payload range, for $2.5 billion, or $300 million per launch, but cautioned that this price tag did not include a potential upper-stage upgrade.^[80][81]

Rep. Tom McClintock and other groups argue that the Congressional mandates forcing NASA to use Space Shuttle components for SLS amounts to a de-facto non-competitive, single source requirement assuring contracts to existing shuttle suppliers, and calling the Government Accountability Office (GAO) to investigate possible violations of the Competition in Contracting Act (CICA).^[62][82][83]
Opponents of the heavy launch vehicle have critically used the name "Senate launch system".^[42] The Competitive Space Task Force, in September 2011, said that the new government launcher directly violates NASA’s charter, the Space Act, and the 1998 Commercial Space Act requirements for NASA to pursue the "fullest possible engagement of commercial providers" and to "seek and encourage, to the maximum extent possible, the fullest commercial use of space".^[61]

Proposed missions and schedule

Some of the currently proposed NASA Design Reference Missions (DRM) and others include:^{[12][84][85][86][87]}

An Astronaut, possibly part of Exploration Mission 2, performing a Tethering Asteroid capture Maneuver at a Near Earth Object (NEO). The Space Exploration Vehicle is close by, with the Orion Multi-Purpose Crew Vehicle (MPCV) docked to the Deep Space Habitat in the background.

• ISS Back-Up Crew Delivery – a single launch mission of up to four astronauts via a Block 1 SLS/Orion-MPCV without an Interim Cryogenic Propulsion Stage (ICPS) to the International Space Station (ISS) if the Commercial Crew Development program does not come to fruition. This potential mission mandated by the NASA Authorization Act of 2010 is deemed undesirable since the 70 t SLS and BEO Orion would be overpriced and overpowered for the mission requirements. Its current description is “delivers crew members and cargo to ISS if other vehicles are unable to perform that function. Mission length 216 mission days. 6 crewed days. Up to 210 days at the ISS.”
• Tactical Timeframe DRMs
  • BEO Uncrewed Lunar Fly-by – Exploration Mission 1 (EM-1), a reclassification of SLS-1, is a single launch mission of a Block I SLS with ICPS and a Block 1 Orion MPCV (Multi-Purpose Crew Vehicle), with a destination of 70,000 km past the lunar surface, to be conducted by 2017.^[88] Its current description is “Uncrewed Lunar Flyby: Uncrewed mission Beyond Earth Orbit (BEO) to test critical mission events and demonstrate performance in relevant environments. Expected drivers include: SLS and ICPS performance, MPCV environments, MPCV re-entry speed, and BEO operations.”^[84]
  • BEO Crewed Lunar Orbit – Exploration Mission 2 (EM-2), a reclassification of SLS-2, is a single launch mission of a Block I SLS with ICPS and lunar Block 1 Orion MPCV with a liftoff mass around 68.8 t with SLS’ Payload Insertion of 50.7 t, which would be a ten to fourteen day mission with a crew of four astronauts who would spend four days in lunar orbit. Its current description is “Crewed mission to enter lunar orbit, test critical mission events, and perform operations in relevant environments”. The destination for EM-2, as of 2013, is regarded to be a captured asteroid in lunar orbit, to be conducted by no later than 2021.^[88]

Artist's rendering of the proposed Mars Transfer Vehicle (MTV) "Copernicus" that would incorporate NTR propulsion and inflatable habitat technology. A five meter diameter crewed Orion MPCV is docked on the far left.

Artist's rendering of Design Reference Mission 5.0, a Manned mission to Mars with the Descent/Ascent Vehicle on the far left, and the habitat and crewed commuter vehicle, the Small Pressurized Rover (SPR),^[89] on the right. The oxygen producing In-Situ Resource Utilization factory would be emplaced about 1 km away.^[90]

• Strategic Timeframe DRMs
  • GEO mission – a dual launch mission separated by 180 days to Geostationary Orbit. The first launch would comprise an SLS with a CPS and cargo hauler, the second an SLS with a CPS and Orion MPCV. Both launches would have a mass of about 110 t.
  • A set of lunar missions enabled in the early 2020s ranging from Earth Moon Lagrangian point-1 (EML-1) and low lunar orbit (LLO) to a lunar surface mission. These missions would lead to a lunar base combining commercial and international aspects.
    • The first two missions would be single launches of SLS with a CPS and Orion MPCV to EML-1 or LLO and would have a mass of 90 t and 97.5 t respectively. The LLO mission is a crewed twelve day mission with three in Lunar orbit. Its current description is “Low Lunar Orbit (LLO): Crewed mission to LLO. Expected drivers include: SLS and CPS performance, MPCV re-entry speed, and LLO environment for MPCV”.
    • The lunar surface mission set for the late 2020s would be a dual launch separated by 120 days. This would be a nineteen-day mission with seven days on the Moon's surface. The first launch would comprise an SLS with a CPS and lunar lander, the second an SLS with a CPS and Orion MPCV. Both would enter LLO for lunar orbit rendezvous prior to landing at equatorial or polar sites on the Moon. Launches would have masses of about 130 t and 108 t, respectively. Its current description is “Lunar Surface Sortie (LSS): Lands four crew members on the surface of the Moon in the equatorial or Polar Regions and returns them to Earth,” “Expected drivers include: MPCV operations in LLO environment, MPCV uncrewed ops phase, MPCV delta V requirements, RPOD (Rendezvous, Proximity Operations and Docking), MPCV number of habitable days.”
  • Five Near Earth Asteroid (NEA) missions ranging from “Minimum” to “Full” capability are being studied. Among these are two NASA Near Earth Object (NEO) missions in 2026. A 155-day mission to NEO 1999 AO10, a 304-day mission to NEO 2001 GP2, a 490-day mission to a Potentially Hazardous Asteroid such as 2000 SG344, utilizing two Block IA/B SLS vehicles,^[91] and a Boeing proposed NEO mission to NEA 2008 EV5 in 2024. The latter would start from the proposed Earth-Moon L2 based Exploration Gateway Platform. Utilising a SLS third stage the trip would take about 100 days to arrive at the asteroid, 30 days for exploration, and a 235-day return trip to Earth.^[92]
  • Forward Work Martian Moon Phobos/Deimos, a crewed Flexible Path mission to one of the Martian moons. It would include 40 days in the vicinity of Mars and a return Venus flyby.
  • Forward Work Mars Landing, a crewed mission, with four to six astronauts,^[93] to a semi-permanent habitat for at least 540 days on the surface of the red planet in 2033 or 2045. The mission would include in-orbit assembly, with the launch of seven SLS block II heavy lift vehicles (HLVs) with a requirement of each being able to deliver 140 metric tons to low earth orbit (LEO). The seven HLV payloads, three of which would contain nuclear propulsion modules, would be assembled in LEO into three separate vehicles for the journey to Mars; one cargo In-Situ Resource Utilization Mars Lander Vehicle (MLV) created from two HLV payloads, one Habitat MLV created from two HLV payloads and a crewed Mars Transfer Vehicle (MTV), known as "Copernicus", assembled from three HLV payloads launched a number of months later. Nuclear Thermal Rocket engines such as the Pewee of Project Rover were selected in the Mars Design Reference Architecture (DRA) study as they met mission requirements being the preferred propulsion option because it is proven technology, has higher performance, lower launch mass, creates a versatile vehicle design, offers simple assembly, and has growth potential.^[49][94]

One section of the Skylab II Habitat would be made from the SLS Block II upper-stage hydrogen tank, similar to but larger than Skylab. A unique use for the SLS as no other vehicle is presently being designed with an 8 meter diameter upper stage tank.

• Other proposed missions
  • 2024+ Single Shot MSR on SLS, a crewed flight with a telerobotic Mars Sample Return (MSR) mission proposed by NASA's Mars Program Planning Group. The time frame suggests SLS-5, a 105 t Block 1A rocket to deliver an Orion capsule, SEP robotic vehicle, and Mars Ascent Vehicle (MAV). “Sample canister could be captured, inspected, encased and retrieved tele-robotically. Robot brings sample back and rendezvous with a crew vehicle." The mission may also include a “Possible Mars SEP (Solar Electric Power/Propulsion) Orbiter”.^[95]
  • Potential sample return missions to Europa and Enceladus have also been noted.^[96]
  • Deep Space Habitat (DSH), NASA's planned usage of spare ISS hardware, experience, and modules for future missions to asteroids, Earth-Moon Lagrangian point and Mars.^[97]
  • Skylab II, proposal by Brand Griffin, an engineer with Gray Research Inc working with NASA Marshall, to use the upper stage hydrogen tank from SLS to build a 21st-century version of Skylab for future NASA missions to asteroids, Earth-Moon Lagrangian point-2 (EML2) and Mars.^{[98][99][100]}
  • SLS DoD Missions, the HLV will be made available for Department of Defense and other US Government agencies to launch military or classified missions.
  • Commercial payloads, such as the Bigelow Commercial Space Stations have also been referenced.
  • Additionally “Secondary Payloads” mounted on SLS via an Encapsulated Secondary Payload Adapter (ESPA) ring could also be launched in conjunction with a "primary passenger" to maximize payloads.
  • Monolithic telescope mission, SLS has been proposed by Boeing as a launch vehicle for the ATLAST Space Telescope. This could be an 8m monolithic telescope or a 16m deploy-able telescope at Earth-Sun L2.^[101]

One proposed ATLAST telescope concept, a design based on an 8 meter monolithic mirror. The Hubble Space Telescope by comparison is equipped with a 2.5 m main mirror. A telescope with an 8 meter monolithic mirror is only possible with an 8+ meter diameter payload fairing.

• • Solar probe mission, SLS has been proposed by Boeing as a launch vehicle for Solar Probe 2. This probe would be placed in a low perihelion orbit to investigate corona heating and solar wind acceleration to provide forecasting of solar radiation events.^[101]
  • Uranus mission, SLS has been proposed by Boeing as a launch vehicle for a Uranian probe. The rocket would “Deliver a small payload into orbit around Uranus and a shallow probe into the planet’s atmosphere.” The mission would study the Uranian atmosphere, magnetic and thermal characteristics, gravitational harmonics as well as do flybys of Uranian moons.^[101]

A very preliminary and unofficial schedule based on a worst case budget (note that the IA has since been superseded by Block IB) has outlined some early SLS flights as:^[102]

Mission	Targeted date	Variant	Notes
SLS-1/EM-1	December 2017	Block I[12]	Send uncrewed Orion/MPCV on trip around the Moon.
SLS-2/EM-2	2021[103]	Block IB[28]	Send the Orion (spacecraft) with four members to an asteroid that had been robotically captured and placed in lunar orbit two years in advance.[91]
SLS-3	August 2022[102]	Block IA[12]
SLS-4	August 2023[102]	Block IA[12]
SLS-5	August 2024[102]	Block IA[102]	Mars Sample Return Mission[95]
SLS-6	August 2025[102]	Block IA[102]	Crewed "Exploration" Mission: Orion BEO picks up Mars sample & returns to Earth
SLS-7	August 2026[102]	Block IA[102]	Cargo launch
SLS-8	August 2027[102]	Block IA[102]	Crewed launch
SLS-9	August 2028[102]	Block IA[102]	Cargo launch
SLS-10	August 2029[102]	Block IA[102]	Crewed launch
SLS-11	August 2030[102]	Block IA[102]	New configuration, Cargo launch
SLS-12	August 2031[102]	Block IA[102]	Crewed mission
SLS-13	August 2032[102]	Block II[102]	New configuration, Cargo launch