DOUGLAS

Slide 10 of 100

Notes:

Phil Bono's second major objective was the manned exploration of Mars. Although an Apollo-type expendable spacecraft was considered, Bono felt a modified ROMBUS would be cheaper and safer although the less optimal single-stage design inevitably would translate to a 3.5 x higher launch mass in Earth orbit. The Mars-bound vehicle would weigh 3965.758t in its 323-kilometer parking orbit. This illustration depicts the end of the trans-Mars injection (TMI) burn in May 1986. The four TMI propellant tanks (now empty) are jettisoned.

After an interplanetary cruise period of 200 days, the ROMBUS spacecraft fires its engines to enter a 555-km parking orbit around Mars. The mothercraft now has a mass of 984.75t after jettisoning two more empty fuel tanks. A conical 25-tonne Mars Excursion Module (MEM) then departs with a landing crew of three astronauts..

ITEM MASS (kg)

USEFUL PAYLOAD RETURNED TO MARS ORBIT 2,495

M.E.M. ASCENT STAGE (DRY) 1,361

ASCENT PROPELLANT (ISP=426s, v=4572m/s) 7,620

M.E.M. LANDING STAGE (DRY) 6,758

SURFACE PAYLOAD 3,629

LANDING PROPELLANT (ISP=426s, v=549m/s) 3,084

TOTAL 24,947

Mars Excursion Module Weight Summary

The crew would return to the waiting mothercraft in an 11,475-kg Mars ascent vehicle that separates from the empty MEM landing module. Its RL-10 rocket engines consume 7620kg of oxygen & hydrogen propellant during the 4572m/s ascent burn. Finally, 280 days after entering Mars orbit, the ROMBUS spacecraft fires its engines to return to Earth. The remaining two fuel tanks are then jettisoned after the final 3749m/s trans-Earth injection maneuver. The empty 340,194 kg vehicle lands on Earth 330 days later. The total round-trip travel time is 830 days.

The “Deimos” mission would naturally have required some modifications to the basic ROMBUS design, including the addition of two SNAP-8 nuclear reactors for auxiliary power. The 6-crew would have lived inside a toroidal Command Center module which also housed 6300kg of food, oxygen & water (1.27kg/day/person).

DATE	MANEUVER	MASS (kg)	DELTA-V (m/s)
	ROMBUS GROSS WT. IN 323km EARTH ORBIT	3,965,737	3,658
05/09/86	VEHICLE AT MARS ESCAPE	1,747,682
11/25/86	VEHICLE ENTERS 555km MARS ORBIT	984,744	2,347
09/21/87	PREPARE FOR TRANS-EARTH INJECTION	963,879
09/21/87	VEHICLE AT MARS ESCAPE	415,035	3,749
08/16/88	VEHICLE AT EARTH ENTRY (12192m/s AEROBRAKING)	382,830	119
08/16/88	VEHICLE LANDS ON EARTH SURFACE	340,193	171

"Reusable Booster for Logistics and Planetary Exploration" -- Bono,Woodworth & Ursini, IAF XV:th INTERNATIONAL ASTRONAUTICAL CONGRESS PROCEEDINGS 1964/p.547

ITEM	MASS (kg)
USEFUL PAYLOAD RETURNED TO MARS ORBIT	2,495
M.E.M. ASCENT STAGE (DRY)	1,361
ASCENT PROPELLANT (ISP=426s, v=4572m/s)	7,620
M.E.M. LANDING STAGE (DRY)	6,758
SURFACE PAYLOAD	3,629
LANDING PROPELLANT (ISP=426s, v=549m/s)	3,084
TOTAL	24,947