Site news

Site map

Testimonials

About this site

About the author

Mailbox


ADVERTISE


SPONSOR


Searching for details:

The author of this page will appreciate comments, info and imagery related to the subject. Please contact Anatoly Zak.


 

Ares-Centaur

Above: One of proposed configurations of NASA's Ares I booster included a Centaur upper stage (right). Credit: NASA

Bookmark and Share

By Igor Rosenberg and Anatoly Zak


US and Russian space contractors mulled the possibility of joint cargo missions to the lunar orbit, which could support manned expeditions to the Moon.

According to the annual report of RKK Energia, Russia’s leading developer of manned spacecraft, during 2008 the company studied the possibility of launching its workhorse Progress cargo ship into the lunar orbit. The project was conducted under a contract with a leading American aerospace company Lockheed Martin and evaluated the US-built Centaur upper stage as a carrier of the Russian cargo vehicle into the lunar orbit.

According to RKK Energia, the company looked at the possibility of a Progress demo mission to the lunar orbit, along with a possible architecture of the transport system to deliver cargo into the lunar orbit.

The exact flight scenarios considered in the study had not been disclosed, however previous NASA documents showed the possibility of the integration of the Centaur upper stage with the Ares I booster. The Ares I launch vehicle is being developed for NASA’s Constellation program and it has an unmanned payload capacity to the low-Earth orbit of around 30 tons. Speculative estimates also indicate that Centaur equipped with a Russian-built passive docking port, could deliver a seven-ton Progress to the lunar orbit, after its launch by a standard Russian Soyuz booster and the following linkup with the Centaur in the low-Earth orbit.

The Progress cargo ship was instrumental in enabling record-breaking Soviet long-duration missions onboard Salyut space stations and the ship remains a major logistics bridge to the International Space Station. The spacecraft could play a similar role in future lunar missions, however it would need a new launch vehicle and the rocket stage, such as Centaur, to leave the Earth orbit and reach the Moon. Using propulsion capabilities of the upper stage, the Progress could enter lunar orbit and then use its own engines to dock with the lunar orbital space station or with a manned vehicle heading to or returning from the lunar surface. The docking port on Progress enables transfer of rocket propellant from its tanks into another spacecraft with a compatible docking port. On October 2, 2009, RKK Energia and Boeing signed a memorandum of intent in Moscow for joint development of the common docking mechanism based on the Russian system known as APAS for the next-generation spacecraft.

Last year, a review of NASA’s future strategy conducted by a special panel appointed by US president Barack Obama opened door to foreign partners to the meaningful participation in the future US manned space flight. "If international partners are actively engaged, including on the “critical path” to success, there could be substantial benefits to foreign relations, and more resources overall could become available (for achieving the goals of the US manned space flight)," the report said in the summary of its key findings. The recommendation reversed five years of American policy of excluding international partners from providing any key elements of NASA's strategy for the return to the Moon, such as launch vehicles, transport spacecraft or lunar landers.


Estimated trans-lunar injection and lunar orbit capabilities for the Centaur stage:

Centaur model   Centaur SEC Centaur DEC Centaur SEC Centaur DEC
Propulsion system  
1 x RL10A-4-2
2 x RL10A-4-2
1 x RL10A-4-2
2 x RL10A-4-2
Total thrust (vacuum) kgf
10,116
20,231
10,116
20,231
Total thrust (vacuum) kN
99.2
198.4
99.2
198.4
Specific impulse sec
450.5
450.5
450.5
450.5
EDS gross mass kg
22,825
23,050
22,233
22,510
EDS propellant mass kg
20,799
20,800
20,207
20,260
EDS burnout mass kg
2,026
2,250
2,026
2,250
Altitude of the Earth-departure orbit km 200 400
Mission  
TLI
LLO
TLI
LLO
TLI
LLO
TLI
LLO
Mission ideal Delta-V m/s
3150
4450
3150
4450
3150
4450
3150
4450
Stack's initial thrust-to-weight ratio (payload mass with TLI gravity losses) -
0.2519
0.3108
0.4983
0.6187
0.2585
0.3194
0.5110
0.6348
TLI maneuver gravity losses m/s
74
51
23
16
59
41
18
12
Mission actual Delta-V (with TLI gravity losses) m/s
3,224
4,501
3,173
4,466
3,209
4,491
3,168
4,462
Mission max payload (without TLI gravity losses) kg
17,975
9,942
17,752
9,719
17,405
9,601
17,232
9,408
Mission max payload (with TLI gravity losses) kg
17,333
9,727
17,549
9,651
16,906
9,433
17,078
9,358
Gross stack mass on LEO (without TLI gravity losses) kg
40,800
32,767
40,802
32,769
39,638
31,834
39,742
31,918
Gross stack mass on LEO (with TLI gravity losses) kg
40,158
32,552
40,599
32,701
39,139
31,666
39,588
31,868

Major assumptions:

  • Centaur upper stage and payload are launched to a 200-kilometer Earth orbit by two separate launch vehicles;
  • Two standard configurations of Centaur were considered: a SEC version with a single engine, DEC – with two engines;
  • Centaur and payload dock in the low-Earth orbit either in a 200-kilometer orbit or in a 400-kilometer orbit;
  • Centaur performs both TLI and LOI maneuvers; 
  • Ideal Delta-V for Trans-lunar Injection, TLI, maneuver - 3,150 meters per second;
  • Ideal Delta-V for Lunar Orbit Insertion, LOI, maneuver - 1,300 meters per second (Russian space agency data); 
  • Ideal Delta-V for Hohmann transfer (a two-impulse transfer) between 200-kilometer and 400-kilometer circular Earth orbits – 116 meters per second;
  • Mass of docking hardware is not included in Centaur mass specifications;
  • Calculations in first two columns are for a fully fueled Centaur (departure from a 200-kilometer Earth orbit);
  • Calculations in last two columns are for a partially fueled Centaur (departure from a 400-kilometer Earth orbit) - extra propellant required to reach a 400-kilometer orbit;

Last update: October 9, 2012

Copyright © 2010 RussianSpaceWeb.com

IMAGE ARCHIVE

Progress

The Progress cargo ship could continue playing a crucial role in logistical support of lunar expeditions. Credit: NASA


docking ring

In 2009, Russian and US aerospace industry officially started cooperation in development of a common docking interface. The work could potentially facilitate joint lunar missions. Click to enlarge. Copyright © 2009 Anatoly Zak