Analysis of Potential for Venus-Bound Cubesat Scientific Investigations

Transcription

1 Analysis of Potential for Venus-Bound Cubesat Scientific Investigations Image Sources: Earth Science and Remote Sensing Unit, NASA Johnson Space Center; JAXA / ISAS / DARTS / Damia Bouic / Elsevier inc.

2 The Case for an Independent icubesat Three Challenges with Interplanetary Missions Budget Risk Launch Opportunities Image Source (Left to Right): Avionews, NASA Ames Research Center, JAXA, Jeff Lysgaard, NASA/JPL, Cagri Kilic

3 What can you do with a TUCAN? the Twelve Unit Cubesat Astronautical Navigator 12U CubeSat 24kg spacecraft in a 30 x 20 x 20 cm frame

4 Agency Mission Target Planet Independent CubeSat Budget (USD) NASA (proposed) NASA (proposed) NASA (proposed) VERITAS Venus <450M DAVINCI Venus <450M VOX Venus <1,000M ESA Venus Express Venus 110M JAXA Akatsuki Venus 290M NASA MarCO Mars 125M Private Group/ University TUCAN Venus <10M

5 Analysis of an Independent CubeSat Mission via FreeFlyer Total Thrust: 2.3 mn Specific Impulse: 3000 s Fuel Mass: 12.5 kg Target Orbit km Altitude Near-circular eccentricity Polar inclination Dry Mass: 11.5 kg Phase Duration Earth Escape Interplanetary Transfer Venus Capture 700 Days 838 Days 785 Days 6.36 years Fuel Left 12.5kg 8.0kg 3.2kg 0.5kg

6 Analysis of an Independent CubeSat Mission mn Thrust Trajectory Analysis Algorithm Phase 1 Phase 2 Phase 3 Backwards propagate from target Venus orbit to determine endpoint of Interplanetary Transfer Frame: Venus, 3-Body Propagate from Earth escape to Venus rendezvous. Refine parameters and determine optimal burns and epochs Frame: Sun, 2-Body Iterate Earth escape parameters to find highest scoring trajectory Visuals Frame: Earth, 2-Body

7 TUCAN Systems A Sample Mission to Venus Can TUCAN employ COTS parts and conduct scientific investigations at another planet?

8 TUCAN Systems Propulsion Two gridded ion thrusters running on solid Iodine propellant Xenon infeasible due to pressurized container restrictions on CubeSat launches I 2 Valve R R Legend Heated Regulator Engine Valve Why two? R R R R Cathode Emitter Ion Thruster Better thrust Better attitude control Redundancy in case of single engine failure or degradation Iodine Reservoir Image Source: Busek Bit Series

9 TUCAN Systems Power Powered by a 0.56 m 2 solar array, with two rotational axes Provides 200 Watts in LEO, 384 Watts in Venus orbit 57 Wh battery

10 TUCAN Systems Onboard Processing CAN and I²C interfaces to onboard sensors 4-48MHz at 1.25 DMIPS/MHz CPU Radiation tests (TID at 20k rad, SEE at 60 MeV) Three microcontroller units fo23r high-priority redundancy and load distribution Image Source: CubeSatShop

11 TUCAN Systems Communications Uplink transmission from Deep Space Network ground station antennas at 19 kw Received by unfolding parabolic antenna onboard the TUCAN Satellite antenna rated at 43.2 db gain Additional 20 db gain from Low Noise Amplifier Downlink signal transmitted at Watts and ground station antenna at 30 db Min 20.8 kbps Max 14.6 kbps Min 13.3 kbps Max 75.1 kbps

12 TUCAN Systems Temperature Control Passive cooling approaches insufficient for Venus solar environment Pump-action cryocoolers produce vibrations which decrease resolution of onboard imaging sensors Solutions such as the conical rotary screw compressor are being developed and offer a great alternative for TUCAN temperature control Image Source: Dmitriev, Olly; et al, An ultra-low vibration cryocooling kit based on a miniature rotary compressor, SSC15-IV-9

13 Scientific Capability 4 kg mass for mission payload Roughly 4U free volume with Venus-facing and orbit-normal sensor placement options Over 300 W available power and three microcontrollers for data accumulation periods Backdrop Image Source: JAXA / ISAS / DARTS / Damia Bouic

14 Mission Goals Science Mission Candidates at Venus The NASA Venus Exploration Analysis Group (VEXAG) defines several goals for scientific exploration at Venus. Among the top are Super-Rotation and Ionosphere Holes Can they be studied via TUCAN?

15 Mission Goals Lower Atmospheric Study One is to understand the mechanisms that lead to atmospheric superrotation. More complete observational data is needed for the troposphere and lower mesosphere in the following areas: Atmospheric temperatures Wind velocities Vertical composition

16 Image Source:Overview of useful spectral regions for Venus: An update to encourage observations complementary to the Akatsuki mission, published by n Elsevier Inc. Mission Goals Lower Atmospheric Study - Equipment Argus 1000 IR Spectrometer Volume: 0.25U 180 cm 3 Mass: 215 g Operating Range: μm Spectral Resolution: 6 nm 256 element array Night Day side altitudes of 0-40 km and night side altitudes of km are visible in these ranges Day (μm)

17 Mission Goals Ionospheric Holes Investigation The discovery and confirmation of hole anomalies in the ionosphere of Venus have been established by both Pioneer Venus Orbiter (PVO) and VEX missions. If ionospheric holes are the result of IMF Blanketing, they should disappear during high intensity solar wind dynamic pressures. Characterized by an increase in magnetic force of 10 nt to 50 nt above relative area strength. Image Source:Journal of Geophysical Research: Space Physics; The extension of ionospheric holes into the tail of Venus

18 Mission Goals Ionospheric Holes Investigation - Equipment NSS Magnetometer: Volume: 0.1 U (6.9 cm x 4.5 cm x 2.0 cm) Mass: 67g Anisotropic Magneto-Resistance Sampling Rate: 10 Hz Resolution: 8 nt Ion and Neutral Mass Spectrometer: Volume: 1.5 U (8 cm x 8 cm x 13 cm) Mass: 560g Thermionic ionizer for neutral particles Adjustable electronic gate pulse as mass filter Sampling Rate: 10 ms/frame Mass resolution: 12 M/dM Dynamic Mass Range: 1-40 amu.

19 Biggest Challenges Component reliability and longevity Batteries require validation testing for longer mission durations Ion engines require testing for extended burn periods Power management systems will require modification to meet system loads Adequate communications downlink Interplanetary navigation software for CubeSats

20 Opening the Solar System with TUCAN The TUCAN mission platform supports countless payload options Private or university groups seeking to send their payload to another world would now have the option of doing so via the TUCAN platform Potential for the Moon or Mars TUCAN is capable of independent travel to other nearby bodies in the system Analysis coming soon for upgraded platform options able to reach the asteroid belt or Jupiter and its moons Large launch windows As a secondary payload on launch vehicles, opportunities occur frequently

21 Thermal Analysis Conducted in Solidwork 2017 Simulation Study Simulation of incident heat flux, surface emissivity through black panels, and convection based cooling from temperature control system were modeled to predict thermal load on TUCAN at the two extreme operating environments of a Venus mission Low Earth Orbit Final Venus Orbit

22 Communication System Analysis Baseline Parameters: Bandwidth = Hz, only a portion of the DSN s 90 MHz for Downlink Communication Frequency = 2.29 GHz, within DSN s Rx range Cubesat gain = 65.2dB gain (43.2 db antenna, 20dB LNA) DSN Gain = 30dB. Low estimation for the 34 m parabolic antennas Thermal noise of the system found using Johnson-Nyquist formula Free space path loss found based on distance and frequency Signal power factors in the Tx Power, the gain of each components, thermal noise, and path loss Bit rate capacity calculated with the Shannon-Hartley theorem.

23 Trajectory Analysis Algorithm Visuals Phase 1 Phase 2 Phase 3 Backwards propagate from target Venus orbit to determine endpoint of Interplanetary Transfer Frame: Venus, 3-Body Propagate from Earth escape to Venus rendezvous. Refine parameters and determine optimal burns and epochs Frame: Sun, 2-Body Iterate Earth escape parameters to find highest scoring trajectory Return Frame: Earth, 2-Body