Mars Cube One

Mars Cube One is the first spacecraft built to the CubeSat form to operate beyond Earth orbit for a deep space mission. CubeSats are made of small components that are desirable for multiple reasons, including low cost of construction,{{cite news | last = Hotz | first = Robert Lee | title = Headed to Mars - A Big Experiment in Tiny Satellites: Briefcase-sized CubeSats, commonly used in Earth's orbit, take an interplanetary journey | newspaper = Wall Street Journal | date = November 22, 2018 | url = https://www.wsj.com/articles/headed-to-mars-a-big-experiment-in-tiny-satellites-1542891601 | quote = Rapidly approaching Mars are the two smallest and cheapest spacecraft to ever cross between the planets, in the vanguard of what U.S. and European satellite designers hope one day will be swarms of tiny probes prowling the solar system.}} quick development, simple systems, and ease of deployment to low Earth orbit. They have been used for many research purposes, including: biological endeavors, mapping missions, etc. CubeSat technology was developed by California Polytechnic State University and Stanford University, with the purpose of quick and easy projects that would allow students to make use of the technology. They are often packaged as part of the payload for a larger mission, making them even more cost effective.{{Cite journal|last=Hand|first=Eric|date=2015-04-10|title=Thinking inside the box|journal=Science|language=en|volume=348|issue=6231|pages=176–177|doi=10.1126/science.348.6231.176|issn=0036-8075|pmid=25859027|doi-access=free}}

The two Mars Cube One spacecraft are identical and officially called MarCO-A and MarCO-B and were launched together for redundancy; they were nicknamed by JPL engineers as WALL-E and EVE in reference to the main characters in the animated film WALL-E.[https://www.space.com/40457-insight-mars-lander-nasa-cubesat-hitchhikers.html NASA's Mars Cubesats 'Wall-E' and 'Eva' Will Be First at Another Planet]. Elizabeth Howell, Space. 1 May 2018.[https://www.jpl.nasa.gov/news/news.php?feature=7263 NASA's First Image of Mars from a CubeSat]. JPL press release. 22 October 2018 The MarCO mission cost was US$18.5 million.[https://phys.org/news/2018-11-big-tiny-satellites-trailing-mars.html Big test coming up for tiny satellites trailing Mars lander]. Marcia Dunn, PhysOrg. 22 November 2018.

JPL's MarCO engineers view the Mars flyby as a technology demonstration that could lead to many more low-cost, targeted small satellite missions outside of Earth's orbit.{{cite magazine | last = Wallace | first = Mark | title = The Small Satellites Paving The Way For Low-Cost Exploration Of Deep Space: When NASA's next Mars mission takes off this Saturday, it will be accompanied by two small escorts that could transform the future of space exploration. | magazine = Fast Company | date = May 4, 2018 | url = https://www.fastcompany.com/40567982/the-small-satellites-paving-the-way-for-low-cost-exploration-of-deep-space | quote = 'The major aspect to MarCO is that it is truly a technology demonstration and high-risk endeavor, very much in the spirit of NASA,' [MarCO chief engineer Andy] Klesh says. 'We see MarCO as only the first in a long line of small satellite explorers . . . .'}} While keeping an eye on the performance of the MarCO mission, NASA has proposed spending more money on CubeSats as a complement to multi-billion-dollar projects which sometimes face years of delay.{{cite news | last = Fernholz | first = Tim | title = The first interplanetary cubesats pave the way for cheaper space science | work = Quartz | date = November 26, 2018 | url = https://qz.com/1475222/nasa-mars-landing-cubesats-pave-way-for-cheaper-exploration/}}

The launch of Mars Cube One was managed by NASA's Launch Services Program. The launch was scheduled for 4 March 2016 on an Atlas V 401,{{cite web| title=NASA Awards Launch Services Contract for InSight Mission| url=http://www.nasa.gov/press/2013/december/nasa-awards-launch-services-contract-for-insight-mission/ |website=NASA| date=19 December 2013 | access-date=11 December 2014}} but the mission was postponed to 5 May 2018 after a major test failure of an InSight scientific instrument.{{cite news |url=http://apnews.excite.com/article/20151222/us-sci--mars_lander-de6da5a926.html |title=NASA calls off next Mars mission because of instrument leak |work=Excite News |agency=Associated Press |date=22 December 2015 |access-date=22 December 2015}} The Atlas V rocket launched the spacecraft together with InSight, then the two MarCO separated soon after launch to fly their own trajectory to Mars{{Cite web|url=https://www.jpl.nasa.gov/cubesat/missions/marco.php|title=Mars Cube One (MarCO)|website=jpl.nasa.gov}} in order to test CubeSats' endurance and navigation in deep space.[https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=3313&context=smallsat JPL's Advanced CubeSat Concepts for Interplanetary Science and Exploration Missions]. (PDF). Sara Spangelo, Julie Castillo-Rogez, Andy Frick, Andy Klesh, Brent Sherwood. CubeSat Workshop 2015. August 2015.[https://www.jpl.nasa.gov/news/news.php?feature=7115 NASA's First Deep-Space CubeSats Say: 'Polo!']. NASA News. 6 May 2018

During the cruise phase, the two spacecraft were kept about {{cvt|10000|km|abbr=on}} away from InSight at either flank for safety, and the distance was reduced as the three spacecraft approached Mars. The closest flyby distance to Mars was {{cvt|3500|km|abbr=on}}.

File:PIA22833 Farewell to Mars (cropped).jpg

The primary mission of MarCO is to test new miniaturized communication and navigation technologies. They were able to provide real-time communication relay while the InSight lander was in the entry, descent, landing (EDL) phase.{{Cite journal|last=Hodges|first=Richard E.|date=21 February 2017|title=A Deployable High-Gain Antenna Bound for Mars: Developing a New Folded-panel Reflectarray for the First CubeSat Mission to Mars.|journal=IEEE Antennas and Propagation Magazine|volume=59|issue=2|pages=39–49|doi=10.1109/MAP.2017.2655561|bibcode=2017IAPM...59...39H|s2cid=35388830}}

The MarCO spacecraft were launched as a pair (named WALL-E and EVE for the movie characters) for redundancy, and flew at either side of InSight. While there are a large number of CubeSats around Earth, Mars Cube One is the first CubeSat mission to go beyond Earth orbit. This allowed for collection of unique data outside of the Earth's atmosphere and orbit. In addition to serving as communications relays, they also tested the CubeSat components' endurance and navigation capabilities in deep space. Instead of waiting several hours for the information to relay back to Earth directly from the InSight lander, MarCO thus relayed EDL-critical data immediately, (subject only to the 8 minute Mars-Earth transmission time) after the completion of the landing.[https://www.jpl.nasa.gov/news/news.php?feature=7290 NASA InSight Team on Course for Mars Touchdown.] NASA News. 21 November 2018.{{cite news|url=https://www.apnews.com/c121ff6fb2ba45dda7e11cdec2c306d3|title=Big test coming up for tiny satellites trailing Mars lander|last=Dunn|first=Marcia|work=Associated Press|date=22 November 2018}} The information sent to Earth included an image from InSight of the Martian surface right after the lander touched down.[https://www.scientificamerican.com/article/nasas-insight-mission-triumphantly-touches-down-on-mars/# NASA's InSight Mission Triumphantly Touches Down on Mars]. Ian O'Neill, Scientific American. 26 November 2018.[https://www.jpl.nasa.gov/news/news.php?feature=7281 How NASA Will Know When InSight Touches Down]. Andrew Good, NASA News. 16 November 2018.

Without the MarCO CubeSats, InSight would relay the flight information to the Mars Reconnaissance Orbiter (MRO) which does not transmit information as quickly. Seeing the already-present difficulty in communicating with ground control during especially risky situations, various teams set out to revise the way in which data is relayed back to Earth. Previous missions would send data directly to Earth after landing, or to nearby orbiters, which would then relay the information. Future missions may no longer choose to rely on these methods, since CubeSats may be able to improve data relay in real time, as well as reduce the overall mission cost.

{{multiple image |width=|header=Views from MarCO|align=center|caption_align=center|image1=PIA22830 Two Days Till Mars for MarCO, Annotated version.jpg |caption1=Mars (24 November 2018) |width1=230|image2=PIA22742 First Image of Mars from a CubeSat, Figure 1.jpg|caption2=Mars (2 October 2018)|width2=200|image3=PIA22323 First Image from MarCO-B, Annotated Version.jpg|caption3=Earth and Moon (9 May 2018)|width3=200}}

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The design includes two communication-relay CubeSats, built by NASA's Jet Propulsion Laboratory, which are of the 6U specification (10×20×30 cm). A limiting factor to the development of CubeSats is that all necessary components must fit within the frame of the satellite. It must contain the antenna, avionics to control the satellite, a propulsion system, power, and payload.

On board the two CubeSats is an ultra-high frequency (UHF) antenna with circular polarization. EDL information from InSight was transmitted through the UHF band at 8 kbit/s to the CubeSats, and was simultaneously retransmitted at an X band frequency at 8 kbit/s to Earth. MarCO used a deployable solar panel for power, but because of the limitations in solar panel efficiency, the power for the X-band frequency can only be about 5 watts.

For the CubeSats to relay information, they need a high gain antenna (HGA) which is reliable, meets the mass specs, has low complexity, and is affordable to build. A high gain antenna (directional antenna) is one that has a focused, narrow radiowave beamwidth. Three possible types were assessed: a standard microstrip patch antenna, a reflectarray, and a mesh reflector. With the small, flat, size required for the CubeSats, the reflectarray antenna type met all of the mission needs. The components of the reflectarray HGA are three folded panels, a root hinge which connects the wings to the body of the CubeSat, four wing hinges, and a burn wire release mechanism. The antenna panels must be able to withstand temperature changes throughout the mission as well as vibrations during deployment. MarCO relayed EDL-critical data immediately upon landing. These signals arrived on Earth eight minutes later.

The propulsion system features eight cold gas thrusters which control the trajectory, and a reaction control system to adjust their attitude (3D orientation).[http://www.cubesat-propulsion.com/cubesat-propulsion-delivery/ VACCO - CubeSat Propulsion Systems]. VACCO. 2017. On the way to the correct transmission destination, the propulsion system made five small corrections to ensure the two small spacecraft were on the correct trajectory.{{Cite web|url=https://www.space.com/29489-marco-cubesats-mars-landing-2016.html|title=Two Tiny 'CubeSats' Will Watch 2016 Mars Landing|website=jpl.nasa.gov|date=27 May 2015}} Small changes in trajectory early on in the mission's deployment not only saved fuel but also the space which any extra fuel would have taken up, thus conserving volume for other important components inside the spacecraft. MarCO-B (WALL-E) had been leaking propellant gas almost since liftoff, but early assessments indicated it had enough to complete its mission.

Having completed their primary mission, the small spacecraft shall continue in their elliptical orbits around the Sun. Engineers expected them to keep working for a couple weeks after they pass Mars orbit, depending on how long their propellant and electronics last.

File:Marco Antenna.jpg|Marco Cubesat, showing the unfolded Reflectarray antenna

File:PIA20346marsco.jpg|Flight hardware of a Mars Cube One (folded up)

File:MarcoOverview.jpg|Overview of Marco satellite after unfolding

File:MarCO will relay data from InSight to Earth during InSight's descent through Mars' atmosphere.jpg|Illustration of MarCO's relay task

Each MarCO carries a softball-sized radio used to communicate with the ground using X-band, to receive data from InSight using UHF, and to collect tracking measurements for navigation. Their attitude control system is equipped with a star tracker that is used to determine the attitude of the spacecraft.[https://smd-prod.s3.amazonaws.com/science-red/s3fs-public/atoms/files/MarCO_Intro_PPO_2015.pdf MarCO - Mars Cube One]. Slide presentation. NASA/JPL. 28 September 2016. In addition, each MarCO carries a miniature wide-angle camera that is used to verify deployments and to capture outreach images.[https://www.sciencedaily.com/releases/2018/10/181022171358.htm NASA's first image of Mars from a CubeSat]. Science Daily. 22 October 2018.

The Artemis 1 mission to the Moon carried 10 CubeSats as secondary payloads. Each CubeSat was developed by a different team with different goals.{{cite web |last1=Hambleton |first1=Kathryn |title=NASA Space Launch System's First Flight to Send Small Sci-Tech Satellites Into Space |url=https://www.nasa.gov/press-release/nasa-space-launch-system-s-first-flight-to-send-small-sci-tech-satellites-into-space |website=nasa.gov |date=2 February 2016 |access-date=3 February 2016}} In another mission, the LICIA CubeSat was carried by the Double Asteroid Redirection Test probe, which launched in November 2021. LICIA assisted DART by monitoring its impact with an asteroid.{{cite web |url=https://www.cosmos.esa.int/documents/1786001/1845930/4.+DART+Overview+%28A.+Cheng%29.pdf/da9935f1-74b7-9316-e9af-0fb2cc63197c |title=DART Mission Update |last=Cheng |first=Andy |format=PDF |publisher=NASA |date=15 November 2018 |access-date=2019-01-14}}

{{Wikinews|NASA's InSight lander and MarCO craft launch in new mission to Mars}}

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• Curiosity rover
• Deep Space 2, another piggyback probe to Mars
• Exploration of Mars
• ExoMars, orbiter and rover
• Mars 3
• Mars Exploration Rover
• Mars Express orbiter
• Mars Reconnaissance Orbiter
• Mars Science Laboratory
• 2001 Mars Odyssey orbiter

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{{Reflist}}

{{commons category|MarCO}}

• [https://www.jpl.nasa.gov/news/press_kits/insight/appendix/mars-cube-one/ MarsCube One Press kits] at JPL
• {{YouTube|id=dS_Q7BFGuu0|title=MarCO: First Interplanetary CubeSat Mission}}

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