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Mars Cube One

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Mars Cube One (A & B)
Mechanical engineer Joel Steinkraus and systems engineer Farah Alibay, from JPL, holding a full scale model of
Mars Cube One (MarCO)
Mission typeCommunications relay test
Mars flyby
OperatorNASA
Websitewww.jpl.nasa.gov/cubesat/missions/marco.php
Spacecraft properties
Spacecraft type6U CubeSat
ManufacturerJPL
Launch mass13.5 kg (30 lb) each[1]
Start of mission
Launch date5 May 2018 (2018-05-05)[2]
RocketAtlas V 401
Launch siteVandenberg Air Force Base SLC-3E
ContractorUnited Launch Alliance
Orbital parameters
Reference systemHeliocentric
EpochPlanned

Mars Cube One (or MarCO) is a Mars flyby mission consisting of two nanospacecraft, of the 6U CubeSat format, that is planned for launch on 5 May 2018 alongside NASA's InSight Mars lander mission. Mars Cube One is intended to provide a communications link to Earth for InSight during mission critical entry, descent, and landing when InSight will be out of sight from the Earth.[3] Mars Cube One is expected to be the first spacecraft built to the CubeSat form to operate beyond Earth orbit, and they will test CubeSats' endurance and navigation in deep space.

The InSight lander will retransmit its telemetry data soon after landing. Therefore, the MarCO test is not critical for the Insight mission, but it will demonstrate the new relay system and technology for future use in missions to outer Solar System bodies.

Overview

Mars Cube One is expected to be the first spacecraft built to the CubeSat form to operate beyond Earth orbit for an interplanetary mission. CubeSats are small cubic components that are built up to create low cost, quickly developed, and easily developed satellites, perfect for operating at low Earth orbit. They have been used for many research purposes, including: biological endeavors, mapping missions, etc. CubeSat technology was developed by California Polytechnic University and Stanford University, with the purpose of quick and easy projects that would allow students as make use of the technology. They are often packed as part of the payload for a larger mission, making them even more cost effective.[4]

The Mars Cube One spacecraft pair was nicknamed by JPL engineers as WALL-E and Eva, in reference to the main characters in an animated film about space robots.[5]

Launch

The launch of Mars Cube One is being managed by NASA's Launch Services Program. The launch was originally scheduled for 4 March 2016 on an Atlas V 401,[6] but the mission was postponed to 5 May 2018 after a major test failure of an InSight scientific instrument.[7] The Atlas V Booster will launch the spacecraft together with InSight, then the two MarCO will separate and fly their own trajectory to Mars.[8]

Objectives

MarCO A and B monitoring InSight landing (artist concept)

The primary mission of MarCO is to provide real-time communication relay while the InSight lander is in the entry, descent, landing phase.[9]

The MarCO will fly as a pair for redundancy. Over the years, there have been several CubeSats that have been flown around Earth's orbit, but Mars Cube One will go beyond the orbit of the Earth. This will allow for unique data outside of the Earth's atmosphere and orbit. In addition of serving for communication relay, they will also test CubeSat's endurance and navigation in deep space. Instead of several hours for the information to relay back to Earth, the MarCO will retrieve EDL-critical data at a more rapid rate.[9] Without the MarCO CubeSats, InSight would relay the flight information to 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. Current tactics rely on sending data to nearby orbiters, which would then send data through space and back to Earth, or even attempting to send data directly to Earth.[9] Because future missions will no longer be able to rely on these methods, CubeSats will hopefully improve data relays in real time, as well as reduce the overall mission cost.[8]

Design and components

Flight hardware of a Mars Cube One

The design includes two communication-relay CubeSats built by NASA's Jet Propulsion Laboratory which are 6U (10×20×30 cm) each (1U is 10×10×10 cm). A limiting factor to the development of CubeSats is that it must fit all the necessary components into the satellite within a certain size and weight restriction. It must contain an outer structure, the antenna, avionics to control the satellite, a propulsion system, power, and payload.[9]

Relay

On board the two CubeSats will be an UHF antenna which is circularly polarized. The EDL information from InSight will travel through an Ultra-High Frequency (UHF) at 8 kbit/s and the CubeSats will then pick up this data, coupled with an X band frequency which will receive and transmit the information at 8 kbit/s.[9] MarCO will also use a deployable solar panel, but because of the limited amount of power that the solar panel can produce, the power for the X-band frequency can only have a maximum of about 5 Watts.

In order for the CubeSats to be able to relay the information, they need to have a high gain antenna (HGA) which is reliable, meets the mass specs, has low complexity, and is affordable to build. A high gain antenna is one that has a focused, narrow radiowave beam width (directional antenna). Three possible types of antennas were debated upon: a standard microstrip patch antenna, a reflectarray, and a mesh reflector. With the specific size requirement of the CubeSats, the reflectarray antenna type met all of the proper mission-enabling specs. The components of a 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 a varying degree of temperature changes throughout the mission as well as vibrations throughout deployment.[9]

Propulsion

The propulsion system will have two components in order to make sure the CubeSats arrive at the correct locations. They will have four cold gas thrusters which will control the trajectory and their attitude (orientation).[10] On the way to the correct transmission destination, the propulsion system will make five small corrections to ensure the cubes are on the correct trajectory path.[11] Due to the zero gravity conditions in space, a small change in trajectory early on in the mission's deployment will change the path of an object more effectively and with less fuel than if the rocket constantly had a turned on propulsion system. The smaller corrections not only save fuel but also the space which the fuel takes up which is necessary to conserve volume for other important components inside the cube.

Similar launches

The upcoming Exploration Mission 1 to the Moon will carry 13 CubeSats as secondary payload. Each CubeSat will be developed by a different team with different goals.[12]

See also

References

  1. ^ [https://www.jpl.nasa.gov/news/press_kits/insight/download/mars_insight_launch_presskit.pdf Mars InSight Launch Press Kit]. NASA, 2018.
  2. ^ Clark, Stephen (9 March 2016). "InSight Mars lander escapes cancellation, aims for 2018 launch". Spaceflight Now. Retrieved 9 March 2016.
  3. ^ Asmar, Sami; Matousek, Steve (20 November 2014). "Mars Cube One (MarCO) - The First Planetary CubeSat Mission" (PDF). Jet Propulsion Laboratory. Retrieved 2015-05-27.
  4. ^ Hand, Eric (2015-04-10). "Thinking inside the box". Science. 348 (6231): 176–177. doi:10.1126/science.348.6231.176. ISSN 0036-8075. PMID 25859027.
  5. ^ NASA's Mars Cubesats 'Wall-E' and 'Eva' Will Be First at Another Planet. Elizabeth Howell, Space. 1 May 2018.
  6. ^ "NASA Awards Launch Services Contract for InSight Mission". NASA. Retrieved 11 December 2014.
  7. ^ "NASA calls off next Mars mission because of instrument leak". Excite News. Associated Press. 22 December 2015. Retrieved 22 December 2015.
  8. ^ a b "Mars Cube One (MarCO)". jpl.nasa.gov. {{cite web}}: Cite has empty unknown parameter: |dead-url= (help)
  9. ^ a b c d e f Hodges, Richard E. (21 February 2017). "A Deployable High-Gain Antenna Bound for Mars: Developing a New Folded-panel Reflectarray for the First CubeSat Mission to Mars". IEEE Antennas and Propagation Magazine. 59: 39–49 – via IEEE Xplore Digital Library.
  10. ^ VACCO - CubeSat Propulsion Systems. VACCO. 2017.
  11. ^ "Two Tiny 'CubeSats' Will Watch 2016 Mars Landing". jpl.nasa.gov. {{cite web}}: Cite has empty unknown parameter: |dead-url= (help)
  12. ^ Hambleton, Kathryn. "NASA Space Launch System's First Flight to Send Small Sci-Tech Satellites Into Space". nasa.gov. Retrieved 3 February 2016.
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