The Pennsylvania State University
Aerospace 401
ERV 4
Fall 2003
Sean M. Barraclough
Benjamin R. Eastmond
Jessica E. Gatto
Matthew F. Kauffmann
Joel D. Richter
Amber M. Wilson
ERV Configuration
Mission Architecture
Structures
Cylindrical Design
 Monolythic
 Dampening
 Docking Adaptor
 Large Space Uses

Food Storage
 Computer and Communications Equipment
 Entertainment

Structures

Friction Stir Welding

Aluminum Metal Matrix Composites

Magnum Launch Vehicle
 85,000kg
2
launches
Propulsion

Liquid bipropellant system using CH4 as fuel and
O2 as oxidizer

RD-0234-CH = main engine located on lander
T = 442 kN; Isp = 343 sec; m = 390 kg

RD-183 = smaller engines used as thrusters
T = 9.80 kN; Isp = 360 sec; m = 60 kg
Ground Control

Dedicated Ground System


Co-located MCC, POCC, SOCC
Combinations POCC and SOCC

Back-up Ground Station

Manned by minimum number of staff
Communications




Deep Space Network
High Gain Antennae (HGA)
Two Low Gain Antennae (LGA)
Total Communications System




One HGA, 2 m diameter
Two LGA, 0.25 m diameter
Receiver and transmitter, combined measuring 5 m by 2
m
Total weight: 160 kg
Communications

Mars Reconnaissance Orbiter
Orbiter
Earth/
Lander
Launch 2005
DSN
 Intermediary link between
Mars
ERV and DSN
Recon
 Guidance system to help ERV
Communications Relay System
when entering Mar’s orbit
(when in Mars orbit)
 Beacon System
 Monitor overall health of ERV
going to Mars
 Sends out one of 4 carrier
tones indicating ERV health
 Easily detected, low cost,
frees up space on DSN

Beacon System
Command and Data Handling

Completely redundant, no single point failure


Space Shuttle computers



Space Shuttle uses 5 computers, 2 running, 3 as back-up
Mass: 29 kg
550 W power
Our system if trends in new technology continue




9 times faster
30% less electricity
220W power
60% less mass
7kg per computer
Totals
 70kg mass
 1375W electricity
Guidance, Navigation
and Control

Attitude control

Navigation

CT-63X Star Sensor by Ball Aerospace &
Technologies Corp, model CT-633
3-AXIS STABILIZED
CASSINI SPACECRAFT
CCD Imaging System
CT-63X
Guidance, Navigation, and
Control

Inertial Reference Frame Devices

Three gyros that provide attitude reference similar to
system of space shuttle

Mars Reconnaissance Orbiter

Total weight of subsystem: 100kg
Power Subsystem

Orbiter


Solar array
Lander

Nuclear Fission
Reactor
Power Requirements Table
Power Requirements (kWe)
Orbiter
Structure
Lander
N/A
N/A
(20)
(140)
Command and Data
0.78
0.52
Synthesis
N/A
140
Communication
0.06
Propulsion
Power (provided)
Thermal
Life Support
Scientific Instruments
Guidance Nav. & Control
0.1
Thermal

Lander




Powered down during interplanetary cruise
Nuclear reactor: large series of pipes
to dissipate heat when on Mars
Fuel synthesis neutral in heat requirements
Orbiter



Maximum solar radiation when in Earth orbit
Will generate up to 46kW of rejected heat
Average satellite uses 3.4% of dry mass for
thermal subsystem
ISS Radiator
Environmental Control and Life
Support
Physiological





Oxygen regenerated
through electrolysis of
H2O
Reusing CO2 molecular
sieves
Purifying H2O through
thermoelectric process
Ionization & photoelectric
flame detectors; CO2
repressant
Dehydrated food
Psychological




Crew composed of 2 men
& 2 women
Group testing under
stressful conditions
Sandy beach theme
within ERV
Personal locker space
Scientific Instruments



Thermometers, Lidar device, accelerometers,
altimeters, seismometers, & pressure sensors
-M = 570 kg
Multispectral imagery
-M = 250 kg
Robotic Chemical Analysis Laboratory
-M = 2.4 kg
Synthesis

Requirements




Create 80,000 kg propellant within 780 days
Lightweight
Reasonable power draw
Result





S/E-RWGS System
Mass = 490 kg
Power requirement = 140 kW
Hydrogen requirement = 4,570 kg
Mass Savings: 93.675%
Cost Analysis
Estimated Cost Per ERV Assuming Five ERV's Produced
Estimated Cost (millions of FY99 USD)
2500
2000
1500
1000
uncrewed
500
crewed
0
0.5
0.6
0.7
0.8
Learning Curve
0.9
1
Future Work
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
For the structures system we need to finalize exactly what subsystems will be on the orbiter and what subsystems will remain on the lander. This will be
an important step in determining where the center of mass will be. We also need to obtain the exact amount of propellant needed for station keeping of
the orbiter and any other maneuvers that will not be as fuel-expensive. Finally we will have to make final material selections in order to minimize our
mass per component. This will be a lengthy process that will require detailed structural analysis of the ERV and its individual components.
The packaging of the ERV inside the launch vehicle payload fairing must be analyzed to ensure the space is used as efficiently as possible. In addition,
the launch location should be decided.
The propulsion subsystem still needs the exact location on the ERV’s structure for all engines to be found. The main engine was postulated to be
toward the lower end of the spacecraft, however, the other two smaller engines used for thrusters have to be placed in a specific region on the ERV.
The feasibility of all the aspects of our ground control system needs to be revisited, along with finding out a total cost estimate for the subsystem. Space
to ground data rates need to be determined and required data handling established. The communications links need to be selected and the actual
layout of our ground system determined.
We need to find data rates for the high gain antennae and figure out if our estimated size for the dish will be large enough to handle the data transmitting
requirements of the ERV. We also need to find out the cost of all the parts of the subsystem. The placement of the antennas on the structure needs to
be determined along with the shielding they will need. We need to figure out the actual shielding requirement as well. Lastly we need to find and actual
transmitter and receiver system to run the antennas.
No mass or power requirement information has been found about components of the C&DH subsystem except for the computers. The computers
require more mass and much more power than the rest of the subsystem, but other factors, such as cabling will affect the total mass and power
requirements. Future work will include finding information about other components of the C&DH subsystem to determine more accurately the mass and
power they require.
For the guidance navigation and control subsystem we need to find out several values. First we need to learn more about the IMU’s, such as exactly
how they work, exactly how big they need to be for a spacecraft our size, and how much they will weigh. After all this is determined we need to find out
how much power, overall these will consume. Since we were able to find and exact star tracker we wanted to use for our ERV the only part we have left
there is discovering where it needs to be placed how it needs to work in with all the other subsystems. Lastly we need to learn more about how the
thrusters will work to control the attitude and this will affect the overall propulsion of the ERV.
The requirements of the power subsystem are very specific based on what every other subsystem needs. Unfortunately there is uncertainty about the
power requirements for many subsystems at this point, and some have no estimate at all yet. As the other subsystems are better defined, the power
subsystem estimate will need to be modified to stay current.
The thermal subsystems of the orbiter and lander have been calculated based on mass ratios of thermal subsystems on Earth orbiting satellites. This
does not result in a very accurate approximation; data from the ISS and the space shuttle should be gathered. Additionally, a simple mathematical
model of the thermal balance will need to be performed to verify other estimates. These two tasks will greatly improve the quality of the estimates.
Further research needs to be completed on the weight of the actual systems of ECLSS. For example, the exact weight of the molecular sieves
collecting the excess carbon dioxide, the weight of the equipment used in the electrolysis and thermoelectric regenerative processes of wastewater, and
the dimensions and mass of the refrigerating units/storage areas for food.
The multispectral imagery aspect of the scientific instruments needs to be investigated further. There may be an alternative method to complete the
same tasks but with a significant drop in weight.
For the synthesis subsystem, we need to determine the volume of the system as a whole. We are currently assuming that if the system is done creating
propellant by the time the crew arrives, it should have no problem creating sufficient oxygen and water to keep them supplied during their stay. This
assumption will have to be verified.
Future Work (seriously)
Power Estimates for ALL subsystems
 Reduce Mass to adhere to Magnum
Booster
 Detailed Structural design and
optimization
 More accurate cost analysis

Questions?