Computer-design drawing for NASA's 2020 Mars Rover
| |
| Mission type | Rover |
|---|---|
| Operator | NASA / JPL |
| Website | http://mars.jpl.nasa.gov/mars2020/ |
| Mission duration | Planned: 1 Mars year |
| Spacecraft properties | |
| Manufacturer | Jet Propulsion Laboratory |
| Launch mass | Rover: 1,050 kg (2,315 lb) |
| Dimensions | Rover: 3 × 2.7 × 2.2 m (9.8 × 8.9 × 7.2 ft) |
| Power | 110 watts |
| Start of mission | |
| Launch date | NET July 2020 |
| Rocket | Atlas V 541 |
| Launch site | Cape Canaveral SLC-41 |
| Mars rover | |
| Spacecraft component | Rover |
Mars 2020 is a Mars rover mission by NASA's Mars Exploration Program with a planned launch in July or August 2020. It will investigate an astrobiologically relevant ancient environment on Mars, investigate its surface geological processes and history, including the assessment of its past habitability, the possibility of past life on Mars, and the potential for preservation of biosignatures within accessible geological materials. It will cache sample containers along its route for a potential future Mars sample-return mission.
The as-yet unnamed Mars 2020 mission was announced by NASA on 4 December 2012 at the fall meeting of the American Geophysical Union in San Francisco. The rover's design is derived from the Curiosity rover, and will use many components already fabricated and tested, but it will carry different scientific instruments and a core drill.
In November 2018, NASA announced that Jezero crater on Mars will be the landing site for the Mars 2020 rover, which is to launch on 17 July 2020, and touch down on Mars on 18 February 2021.
Mission overview
Artist concept of the Mars 2020 rover
The mission will seek signs of habitable conditions on Mars in the ancient past, and will also search for evidence —or biosignatures— of past microbial life. The rover is planned for launch in 2020 on an Atlas V-541, and the Jet Propulsion Laboratory will manage the mission. The mission is part of NASA's Mars Exploration Program.
The Science Definition Team proposed that the rover collect and
package as many as 31 samples of rock cores and surface soil for a later
mission to bring back for definitive analysis on Earth. In 2015,
however, they expanded the concept, planning to collect even more
samples and distribute the tubes in small piles or caches across the
surface of Mars.
In September 2013 NASA launched an Announcement of Opportunity
for researchers to propose and develop the instruments needed, including
the Sample Caching System.
The science instruments for the mission were selected in July 2014
after an open competition based on the scientific objectives set one
year earlier. The science conducted by the rover's instruments will provide the context needed for detailed analyses of the returned samples.
The chairman of the Science Definition Team stated that NASA does not
presume that life ever existed on Mars, but given the recent Curiosity rover findings, past Martian life seems possible.
Objectives
The
Mars 2020 rover will explore a site likely to have been habitable. It
will seek signs of past life, set aside a returnable cache with the most
compelling rock core and soil samples, and demonstrate technology
needed for the future human and robotic exploration of Mars.
A key mission requirement is that it must help prepare NASA for its long-term Mars sample-return mission and crewed mission efforts. The rover will make measurements and technology demonstrations to help designers of a future human expedition understand any hazards posed by Martian dust, and will test technology to produce a small amount of pure oxygen (O
2) from Martian atmospheric carbon dioxide (CO
2). Improved precision landing technology that enhances the scientific value of robotic missions also will be critical for eventual human exploration on the surface. Based on input from the Science Definition Team, NASA defined the final objectives for the 2020 rover. Those become the basis for soliciting proposals to provide instruments for the rover's science payload in the spring 2014.
2) from Martian atmospheric carbon dioxide (CO
2). Improved precision landing technology that enhances the scientific value of robotic missions also will be critical for eventual human exploration on the surface. Based on input from the Science Definition Team, NASA defined the final objectives for the 2020 rover. Those become the basis for soliciting proposals to provide instruments for the rover's science payload in the spring 2014.
The mission will also attempt to identify subsurface water, improve landing techniques, and characterize weather, dust, and other potential environmental conditions that could affect future astronauts living and working on Mars.
Design
Powered Descent Vehicle, part of the sky crane landing system
Full-size model of the rover wheels
The three major components of the Mars 2020 spacecraft are the cruise stage for travel between Earth and Mars; the Entry, Descent, and Landing System (EDLS) that includes the aeroshell, parachute, descent vehicle, and sky crane; and the rover.
The rover is based on the design of Curiosity.
While there are differences in scientific instruments and the
engineering required to support them, the entire landing system
(including the sky crane
and heat shield) and rover chassis can essentially be recreated without
any additional engineering or research. This reduces overall technical
risk for the mission, while saving funds and time on development.
One of the upgrades is a guidance and control technique called
"Terrain Relative Navigation" to fine-tune steering in the final moments
of landing. In October 2016, NASA reported using the Xombie rocket to test the Lander Vision System (LVS), as part of the Autonomous Descent and Ascent Powered-flight Testbed (ADAPT) experimental technologies, for the Mars 2020 mission landing.
A Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), left over as a backup part for Curiosity during its construction, will power the rover. The generator has a mass of 45 kilograms (99 lb) and uses 4.8 kilograms (11 lb) of plutonium dioxide as the source of steady supply of heat that is converted to electricity; the electrical power generated is approximately 110 watts at launch with little decrease over the mission time. Two lithium-ion rechargeable batteries
are included to meet peak demands of rover activities when the demand
temporarily exceeds the MMRTG's steady electrical output levels. The
MMRTG offers a 14-year operational lifetime, and it was provided to NASA
by the US Department of Energy.
Unlike solar panels, the MMRTG provides engineers with significant
flexibility in operating the rover's instruments even at night and
during dust storms, and through the winter season.
Engineers redesigned the Mars 2020 rover wheels to be more robust than Curiosity's wheels, which have sustained some damage. The rover will have thicker, more durable aluminium wheels, with reduced width and a greater diameter (52.5 cm, 20.7 in) than Curiosity's 50 cm (20 in) wheels. The aluminium wheels are covered with cleats for traction and curved titanium spokes for springy support.
The combination of the larger instrument suite, new Sampling and
Caching System, and modified wheels makes Mars 2020 heavier than its
predecessor, Curiosity.
The rover mission and launch are estimated to cost about US$2.1 billion. The mission's predecessor, the Mars Science Laboratory, cost US$2.5 billion in total. The availability of spare parts make the new rover somewhat more affordable. Curiosity's engineering team are also involved in the rover's design.
Scientific instruments
Proposed Mars 2020 rover payload
Based on the scientific objectives, nearly 60 proposals for rover instrumentation were evaluated and, on 31 July 2014, NASA announced the payload for the rover:
- Planetary Instrument for X-Ray Lithochemistry (PIXL), an X-ray fluorescence spectrometer to determine the fine scale elemental composition of Martian surface materials.
- Radar Imager for Mars' subsurface experiment (RIMFAX), a ground-penetrating radar to image different ground densities, structural layers, buried rocks, meteorites, and detect underground water ice and salty brine at 10 m (33 ft) depth.
- Mars Environmental Dynamics Analyzer (MEDA), a set of sensors that measure temperature, wind speed and direction, pressure, relative humidity, radiation, and dust size and shape. It will be provided by Spain's Centro de Astrobiología.
- Mars Oxygen ISRU Experiment (MOXIE), an exploration technology investigation that will produce a small amount of oxygen (O
2) from Martian atmospheric carbon dioxide (CO
2). This technology could be scaled up in the future for human life support or to make the rocket fuel for return missions. - SuperCam, an instrument suite that can provide imaging, chemical composition analysis and mineralogy in rocks and regolith from a distance. It is an upgraded version of the ChemCam on the Curiosity rover but with two lasers and four spectrometers that will allow it to remotely identify biosignatures and assess the past habitability.
- Mastcam-Z, a stereoscopic imaging system with the ability to zoom.
- Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC), an ultraviolet Raman spectrometer that uses fine-scale imaging and an ultraviolet (UV) laser to determine fine-scale mineralogy and detect organic compounds.
- Mars Helicopter Scout (MHS) is a planned solar powered helicopter drone with a mass of 1.8 kg (4.0 lb) that is expected to help pinpoint interesting targets for study and plan the best driving route for the rover. The small helicopter is expected to fly up to five times during its 30-day testing, and will fly no more than 3 minutes per day. It is a technology demonstrator that will form the foundation on which more capable helicopters can be developed for aerial exploration of Mars and other planetary targets with an atmosphere.
- Microphones will be used during the landing event, while driving, and when collecting samples.
- 23 cameras in total are included in the Mars 2020 rover.
Mars 2020 rover instruments
23 cameras
Proposed adaptive caching for sample return
Proposed landing sites
In May 2017, evidence of the earliest known life on land may have been found in 3.48-billion-year-old geyserite, a mineral deposit often found around hot springs and geysers, uncovered in the Pilbara Craton of Western Australia. These findings may be helpful in deciding where best to search for early signs of life on the planet Mars. The following locations are the eight landing sites that were under consideration for Mars 2020:
- Columbia Hills, in Gusev Crater
- Eberswalde Crater
- Holden Crater
- Jezero crater
- Mawrth Vallis
- Northeastern region of Syrtis Major Planum
- Nili Fossae
- Southwestern region of Melas Chasma.
A workshop was held on 8–10 February 2017 in Pasadena, California, to
discuss these sites, with the goal of narrowing down the list to three
sites for further consideration. The selected sites are:
- Jezero crater
- Northeastern region of Syrtis Major Planum
- Columbia Hills, in Gusev Crater, where the Spirit rover landed.
Proposed landing site – Jezero crater (18.855°N 77.519°E)
Jezero and surrounding region
Jezero crater on Mars - ancient rivers (on the left) fed the crater; overflow flooding carved the outlet canyon (on the right).
Jezero delta – chemical alteration by water
In November 2018, it was announced that Jezero crater was chosen as the planned landing site for Mars 2020 rover.
Mars sample-return mission
Sample-return concept
A Mars sample-return mission (MSR) would be a spaceflight mission to collect rock and dust samples on Mars and then return them to Earth.
Sample-return would be a very powerful type of exploration, because
analysis is freed from the time, budget, and space constraints of
spacecraft sensors.
According to Louis Friedman, Executive Director of The Planetary Society,
a Mars sample-return mission is often described by the planetary
science community as one of the most important robotic space missions,
due to its high expected scientific return on investment.
Over time, several concept missions has been studied, but none of
them got beyond the study phase. The three latest concepts for a MSR
mission are a NASA-ESA proposal, a Russian proposal (Mars-Grunt), and a Chinese proposal.
Scientific value
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Mars meteorites in a Museum
The return of Mars samples would be beneficial to science by allowing
more extensive analysis to be undertaken of the samples than could be
done by instruments painstakingly transferred to Mars. Also, the
presence of the samples on Earth would allow scientific equipment to be
used on stored samples, even years and decades after the sample-return
mission.
In 2006, MEPAG
identified 55 important future science investigations related to the
exploration of Mars. In 2008, they concluded that about half
of the investigations "could be addressed to one degree or another by
MSR", making MSR "the single mission that would make the most progress
towards the entire list" of investigations. Moreover, it was found that a
significant fraction of the investigations cannot be meaningfully
advanced without returned samples.
One source of Mars samples is what are thought to be Martian meteorites, which are rocks ejected from Mars that made their way to Earth. Of over 61,000 meteorites that have been found on Earth, 132 were identified as Martian as of 3 March 2014.[5]
These meteorites are thought to be from Mars because they have
elemental and isotopic compositions that are similar to rocks and
atmosphere gases analyzed by spacecraft on Mars.
In 1996 the possibility of life on Mars was questioned again when apparent microfossils might have been found in a Mars meteorite (see ALH84001). This led to a renewed interest in a Mars sample-return, and several different architectures were considered. NASA administrator Goldin laid out three options for MSR: "paced", "accelerated", and "aggressive".
It was thought that MSR could be done for less than 100 million USD per
year, with something similar to then-current Mars exploration budgets.
History
Artist concept of a Mars sample-return mission, 1993
For at least three decades, Western scientists have advocated the return of geological samples from Mars. One concept was studied with the Sample Collection for Investigation of Mars
(SCIM) proposal, which involved sending a spacecraft in a grazing pass
through Mars upper atmosphere to collect dust and air samples without
landing or orbiting.
The Soviet Union considered a Mars sample-return mission, Mars 5NM, in 1975 but it was cancelled due to the repeated failures of the N1 rocket that would have been used to launch it. A double sample-return mission, Mars 5M (Mars-79) planned for 1979, was cancelled due to complexity and technical problems.
One mission concept (provisionally named simply Mars Sample-Return) was originally considered by NASA's Mars Exploration Program to return samples by 2008, but was cancelled following a review of the program. A NASA-ESA concept mission was aborted in 2012.
The United States' Mars Exploration Program, formed after Mars Observer's failure in September 1992, supported a Mars sample-return. One example of a mission architecture was the Groundbreaking Mars Sample-Return by MacPhereson in the early 2000s.
In early 2011, the National Research Council's Planetary Science Decadal Survey, which laid out mission planning priorities for the period 2013–2022 at the request of NASA and the NSF, declared a MSR campaign its highest priority Flagship Mission for that period. In particular, it endorsed the proposed Mars Astrobiology Explorer-Cacher (MAX-C) mission in a "descoped" (less ambitious) form, although this mission plan was officially cancelled in April 2011.
In September 2012, the United States' Mars Program Planning Group
endorsed a sample-return after evaluating long-term Mars' plans.
The key mission requirement for the planned Mars 2020 rover is that it must help prepare NASA for its MSR campaign,. which is needed before any crewed mission takes place. Such effort would require three additional vehicles: an orbiter, a fetch rover, and a Mars ascent vehicle (MAV).
NASA–ESA concept
Ascent vehicle in its protective shroud, 2009 ESA-NASA design.
In mid-2006, the international Mars Architecture for the Return of Samples (iMARS) Working Group was chartered by the International Mars Exploration Working Group
(IMEWG) to outline the scientific and engineering requirements of an
internationally sponsored and executed Mars sample-return mission in the
2018–2023 time frame.
In October 2009, NASA and ESA established the Mars Exploration Joint Initiative to proceed with the ExoMars mission, whose ultimate aim is "the return of samples from Mars in the 2020s". A first step in this was one particular proposal, a joint project between NASA and ESA called ExoMars, would launch in 2018 with unspecified missions to return the sample itself expected in the 2020–2022 time frame. The cancellation of the caching rover MAX-C and later NASA withdrawal from ExoMars, pushed back a sample-return mission to an undetermined date.
Due to budget limitations the MAX-C mission, which was the first NASA-ESA mission leading to a MSR, was canceled in 2011 and the overall plan in 2012. The pull-out was described as "traumatic" for the science community. However, in April 2018, a letter of intent was signed by NASA and ESA that may provide a basis for a Mars sample-return mission.
NASA proposals
In September 2012, NASA announced its intention to further study
several strategies of bringing a sample of Mars to Earth – including a
multiple launch scenario, a single-launch scenario and a multiple-rover
scenario – for a mission beginning as early as 2018.
Dozens of samples would be collected and cached by the Mars 2020 rover,
and would be left on the surface of Mars for possible later retrieval. A "fetch rover" would retrieve the sample caches and deliver them to a Mars ascent vehicle (MAV). In July 2018 NASA contracted Airbus to produce a "fetch rover" concept. The MAV would launch from Mars and enter a 500 km orbit and rendezvous with a new Mars orbiter.
The sample container would be transferred to an Earth entry vehicle
(EEV) which would bring it to Earth, enter the atmosphere under a
parachute and hard-land for retrieval and analyses in specially designed
safe laboratories.
Two-launches architecture
In
this scenario, the sample-return mission would span two launches at an
interval of about four years. The first launch would be for the orbiter,
the second for the lander. The lander would include the Mars Ascent Vehicle (MAV).
Three-launches architecture
This concept is to have the sample-return mission split into a total of three launches. In this scenario, the sample-collection rover (e.g. Mars 2020
rover) would be launched separately to land on Mars first, and carry
out analyses and sample collection over a lifetime of at least 500 Sols
(Martian days).
Some years later, a Mars orbiter would be launched, followed by the lander including the Mars Ascent Vehicle
(MAV). The lander would bring a small and simple "fetch rover", whose
sole function would be to retrieve the sample containers from the caches
left on the surface or directly from the Mars 2020 rover, and return
them to the lander where it would be loaded onto the MAV for delivery to
the orbiter and then be sent to Earth.
This design would ease the schedule of the whole mission, giving
controllers time and flexibility to carry out the required operations.
Furthermore, the program could rely on the successful landing system
developed for the Mars Science Laboratory, avoiding the costs and risks associated with developing and testing yet another landing system from scratch.
SCIM
Artist concept of SCIM passing through the Martian atmosphere
SCIM (Sample Collection for Investigation of Mars) was a low-cost low-risk Mars sample-return mission design, proposed in the Mars Scout Program. SCIM would return dust and air samples without landing or orbiting, by dipping through the atmosphere as it collects Mars material. It uses heritage from the successful Stardust and Genesis sample-return missions.
Additional plans
Russia
A Russian Mars sample-return mission concept is Mars-Grunt. It is meant to use Fobos-Grunt design heritage. Plans as of 2011 envisioned a two-stage architecture with an orbiter and a lander (but no roving capability), with samples gathered from the immediate surroundings of the lander by a robotic arm.
China
China has plans for a Mars sample-return mission by 2030.
The mission plan combines elements of remote sensing of the surface,
soft landing, using a rover to gather samples, then sample-return.
France
France has worked towards a sample-return for many years. This included the preparation of laboratories for returned samples, and numerous proposals.
They worked on the development of a Mars sample-return orbiter, which
would capture and return the samples as part of a joint mission with
either the United States, or other European countries.
Japan
On 9 June 2015, the Japanese Aerospace Exploration Agency (JAXA) unveiled a plan named Martian Moons Exploration (MMX) to retrieve samples from one of the moons of Mars. This mission will build on the expertise to be gained from the Hayabusa 2 and SLIM missions. Of the two moons,
Phobos's orbit is closer to Mars and its surface may have adhered
particles blasted from the red planet; thus the Phobos samples collected
by MMX may contain material originating from Mars itself. Japan has also shown interest in participating in an international Mars sample-return mission.
Potential for back contamination
Stardust's returned landing capsule
Since it is currently unknown whether life forms exist on Mars, the mission could potentially transfer viable organisms resulting in back contamination—the introduction of extraterrestrial organisms into Earth's biosphere.
The scientific consensus is that the potential for large-scale effects,
either through pathogenesis or ecological disruption, is extremely
small.
Nevertheless, returned samples from Mars will be treated as potentially
biohazardous until scientists can determine that the returned samples
are safe. The goal is to reduce the probability of release of a Mars
particle to less than one in a million.
In addition, the proposed NASA Mars Sample-return mission will not be
approved by NASA until the National Environmental Policy Act (NEPA)
process has been completed.
The NEPA process would require a public review of all potential impacts
that could result from MSR, including worst case back contamination
scenarios. It is likely that a formal Environmental Impact Statement
(EIS) would have to be prepared. Furthermore, under the terms of Article VII of the Outer Space Treaty
and probably various other legal frameworks, were a release of
organisms to occur, the releasing nation or nations would be liable for
any resultant damages.
Part of the sample-return mission would be to prevent contact
between the Martian environment and the exterior of the sample
container.
In order to eliminate the risk of parachute failure, the current plan
is to use the thermal protection system to cushion the capsule upon
impact (at terminal velocity). The sample container will be designed to withstand the force of the impact. To receive the returned samples, NASA proposed a specially designed Biosafety Level 4 containment facility, the Mars Sample-Return Receiving facility (MSRRF). Not knowing what properties (e.g., size) any Martian organisms might exhibit is a complication in design of such a facility.
Other scientists and engineers—notably Robert Zubrin of the Mars Society—argue
that contamination risk is functionally zero and there is little need
to worry. They cite, among other things, lack of any verifiable incident
although trillions of kilograms of material have been exchanged between
Mars and Earth due to meteorite impacts.
The International Committee Against Mars Sample Return (ICAMSR) is a small advocacy
group led by Barry DiGregorio, who campaigns against a Mars
sample-return mission. While ICAMSR acknowledges a low probability for
biohazards, it considers the proposed containment measures insufficient,
and unsafe at this stage. ICAMSR is demanding more in situ
studies on Mars first, and preliminary biohazard testing at the
International Space Station before the samples are brought to Earth. DiGregorio also supports the conspiracy theory of a NASA coverup regarding the discovery of microbial life by the 1976 Viking landers.
ICAMSR also supports a fringe view that several pathogens -such as
common viruses- originate in space and probably caused some of the mass extinctions, and deadly pandemics. Claims connecting terrestrial disease and extraterrestrial pathogens have been rejected by the scientific community.
NASA Sample-Return Robot Challenge
The
Sample-Return Robot Challenge, as part of NASA's Centennial Challenges
program, offered a total $1.5 million to teams that can build fully
autonomous robots that can find, retrieve, and return up to 10 different
sample types within a large outdoor environment (80,000 m2).
The challenge started in 2012 and ended in 2016. Over 50 teams competed
during the 5-year history of the NASA Challenge. A robot named
Cataglyphis, developed by Team Mountaineers from West Virginia
University completed the final challenge in 2016.
In popular culture
- Life (2017 film) - Fictional story set in the near future, centres around a robotic Mars sample-return space probe, which returns to the International Space Station with soil samples potentially containing evidence of extraterrestrial life. Despite taking careful precautions, the lives of the crew become endangered. The choice between personal safety and the risk of infecting Earth is an important theme in the film.
Mars 2020 Mission timeline
Mars 2020 mission timeline (as of July 2013).
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