Powered Re-entry Vehicle David Lammers ASTE 527 Concept 13 December 2011

Why and What is Powered Re-entry? Take advantage of on orbit refueling ΔV burn to decrease re-entry velocity Light weight Lower heat of re-entry = no heavy heat shield tiles Easier on passengers (lower decelerations) Easier on vehicle = reusability Unlimited cross range capability – Land anywhere on the Earth you desire

Fuel Depot Game changing technology to utilize future on-orbit fuel depots

Powered Re-entry Vehicle Small vehicle –Lightweight –Decreases up and down propellant requirement Designed for a small crew only –3-6 astronauts Horizontal landing –May incorporate air breathing/turboprop propulsion for in-atmosphere range extension

PRV Must be delivered to space – Ex. X-37 X-37 architecture Build on sub-orbital platform – Space Ship 2, Lynx, Super Mod, etc. Low weight materials – Carbon composites – Less (or no)TPS

Case Study: X-37 Phased design Designed for a 3.1 km/s ΔV and 270 days in orbit launch weight of ~ 5000 kg Upgraded X-37C design announced 2011 – % scale of X-37B – Carry up to 6 astronauts in modified cargo bay Reported Cost ($ in millions) 1999: NASA 109, USAF 16, Boeing : Boeing awarded additional 310 under SLI Total of $500 million

Case Study: Space Ship Two Suborbital (~110km) Max velocity ~ Mach 3 (SS1) Increase drag through “feathering” – Highly stable – Low skin temperature Allows use of light weight carbon composites without heat shield

Velocity Profile of Shuttle

Propellant Requirement Uses Ideal Rocket Equation which neglects all forces other than thrust 1200kg burnout mass 5000kg burnout mass

Size Comparisons of X-37 and Shuttle Shuttle loaded mass 381,600 kg (estimate) –81,600 kg dry mass X-37B loaded mass 4,990 kg –2,600 kg dry mass (estimate)

Reusability is Key Low mechanical stress and low heat buildup on vehicle should lead to a highly reusable system Need to keep turnaround costs down – Est. $450 million per shuttle launch – Ideally the craft could be reused quickly with almost zero cycle cost

Multiple PRV’s Credit: Buzz Aldrin Economies of scale More customers – Nations – Private industry – Individuals

Future Work Feasibility – Would a system like this really work Simulation comparing reentry velocity, drag, delta V, aerothermal simulation, etc. Figure out maximum velocity that the “feathering” technique could be employed – Initial thought it needs to be done at the apex of a trajectory, thus a very low (almost zero) velocity

References eroid_have_wiped_o/impact3.jpg content/uploads/2011/10/fotovoltaico_spaziale.jpg tml blogs.airspacemag.com/.../10/x37-still-aloft/

Powered Re-entry Vehicle

BACKUP SLIDES

Reentry, as it is Now Shuttle – Mach 25 at 120 km – TPS = 8574 kg (30,000 tiles) Includes all types of tiles FRSI, LRSI (FIB), HRSI, and RCC FRSI < 371 C FIB < 649 C HRSI < 1260 C RCC > 1260 C