The goal of the CubeSat Lunar Lander project is to explore the technologies required for building a viable CubeSat device that can orbit and/or land on the moon. This project's predecessor was the Alaskan Ice Buoy Project which assisted in learning about the CubeSat Kit hardware that is also being used in this project.
This project is supported by grants from the Vermont Space Grant Consortium, a part of the NASA Space Grant program. Vermont Technical College has also received generous donations of commercial software from AdaCore, SofCheck, Praxis, and Rowley Associates to support using high integrity software tools and methods in the programming of the system.
Software to analyse orbits of our spacecraft has been supplied as a generous donation by AGI of their Satellite Tool Kit.
Dr. Carl S. Brandon, Principal
Investigator
Dr. Brandon is a professor of Science and Aeronautical Engineering
Technology at Vermont Technical College. Dr. Brandon oversees the project and works on the
satellite communication systems.
Prof. Peter C. Chapin, Software
Director
Prof. Chapin is a professor of Computer Information Systems at Vermont
Technical College. Prof. Chapin is a software developer on the project, working especially
on the high integrity software tool chain used.
Recently on the project:
May 9, 2011: VTC's Summer of Software Engineering project will host two students working full time on CubeSat software development in preparation for the upcoming test launch.
Sep 1, 2010: We have received the source code for the NASA GEONS navigation program.
Aug 2, 2010: We were awarded a NASA launch opportunity for a single CubeSat. The launch will occur in March of 2012. We plan to use this as an opportunity to test the base control program, navigation software, and star tracking camera being developed by Norwich University.
This grant was written with the assistance of Prof. Bill Lakin, Director of Vermont Space Grant, and colleagues at University of Vermont (Prof. Jun Yu) and Norwich University (Prof. Danner Friend). The text below is from the grant application. At the moment, the rest of this site describes the Vermont Tech portion of the grant work.
Introduction: A CubeSat is a payload package having dimensions 10cm x 10cm x 10cm. A recent revision (8/1/09, rev12) of the CubeSat design specifications allows for a mass of up to 1.33 kg. Prior development of launch technology for this payload format has resulted in a significant cost advantage over other types of satellite deployment. In particular, work at the California Polytechnic Institute (Cal Poly) has produced a standard, reliable, and flight proven deployment system. The Poly Picosatellite Orbital Deployer, or P-POD, is a tubular, springloaded mechanism taking up very little space. It can hold up to three CubeSats and be integrated into any launch vehicle, protecting primary payloads from the CubeSats and vice-versa.
New Capabilities: Although a number of CubeSats have previously been developed and launched into Earth orbit, none have used high-energy bi-propellant thrusters or long duration ion thrusters, and none have done interplanetary navigation. The development of a Lunar Lander CubeSat would thus be an important contribution to NASAs mission capabilities and be useful for future CubeSat missions away from low Earth orbit. The faculty and students working on this project will develop expertise in the area of spacecraft design and navigation and forge links between research groups at multiple Vermont institutions as well as links with collaborators at NASA. The resulting opportunities for graduate thesis research and mentored undergraduate research, involving both individuals and groups of students at four Vermont colleges and universities, will make significant contributions to the development of the STEM (Science, Technology, Engineering & Mathematics) workforce.
Chemical Propellant Rocket: Preliminary results obtained in the CubeSat Laboratory of Vermont Technical College (VTC) have indicated the feasibility of designing a single unit CubeSat with a propulsion system capable of following the Apollo lunar landing profile and landing on the Moon from a 100km orbit. The propellant considered is a hypergolic (selfigniting) combination of mono-methyl hydrazine and nitrogen tetroxide (as used in the shuttles orbital maneuvering engines and the Apollo lander). According to preliminary design calculations, the propellant mass fraction for this lander will be within 0.2% of that used on the Apollo Moon lander. A preliminary design has also been developed for a two-unit CubeSat booster (20cm x 10cm x 10cm, 2 kg) using the same propulsion system, but with 1.5kg of propellant. With the single unit lander attached, this package would be capable of generating a delta v of 2,000 m/s, which would be sufficient to leave a geostationary transfer ellipse at the apogee with escape velocity.
Ion Drive Rocket: In addition to refining and prototyping these chemical propellant rocket designs, this project will consider in parallel the development of a two-unit CubeSat solar photovoltaic powered ion drive booster with a propellant load of xenon, giving a delta v of about 4,000 m/s. An ion drive would remove the hypergolic propellants from the booster, and the inert xenon propellant would present no danger to a primary geostationary payload. While emphasis will be on developing a lunar lander package, if launch permission for a hypergolic lunar lander could not be obtained, with an ion drive booster the lander portion of the spacecraft could be replaced with an instrument package for making observations from orbit of the Moon. A spacecraft with ion drive booster would also be capable of reaching Mars. Low Energy Transfer Flight Paths: To have sufficient leeway for lunar orbit insertion and lowering, a low energy transfer strategy will be developed. The required indirect transfer trajectories will have transit times of close to a year. However, indirect transfer can produce considerable savings in energy requirements, making the projected missions possible. The missions in this project will be completely robotic, as the spacecraft will be entirely autonomous. Navigation will be by optical images using sun and star tracking. Optical means will also be used for attitude determination during the descent to the lunar surface, and for measurement of lateral velocity during the landing phase. Optical sensors might also be used for data collection on the lunar surface. The proposed lander will communicate with the booster/orbiter for relay of data collected to Earth through a wireless network involving both stationary and mobile stations. With the low cost of the CubeSats compared with conventional spacecraft, a swarm of a dozen or more landers could be sent to the Moon and communicate among themselves and with the boosters/orbiters. The proposed project will include interactions with NASA colleagues in the Asteroids, Comets & Satellites group at JPL (Jet Propulsion Laboratory) and the Space Weather Laboratory, Heliophysics Science Division at GSFC (Goddard Space Flight Center) as well as assistance from industrial collaborators.
The software for the satellite is written in SPARK, a strict subset of the Ada programming language. This was chosen because of its high integrity and reliability. Once the satellite is deployed, there will be no opportunity to correct software bugs or errors, so a solid program is essential.
Unfortunately, the microcontroller we chose (Texas Instruments MSP430) has no Ada compiler available. In order to combat this, a software toolchain has been created, which can be seen at right.
In detail, the SPARK code written by the developers is run through Praxis Systems' SPARK examiner to ensure that the annotations match the code. The code is then run through SofCheck's AdaMagic compiler, which compiles the Ada code into C code. That C code is then combined with microcontroller device drivers written in C and called from Ada, and it is compiled for the MSP430 platform using Rowley Associates' CrossWorks.