Space tug
In February 2020, MEV-1 successfully docked with Intelsat 901 and returned it to geosynchronous orbit, allowing it to continue operating 4 years past its service life.
MEV-1 will continue to maintain this position for a 5-year period, after which it will move the satellite back into a graveyard orbit for retirement.
[7] Spaceflight Inc. developed SHERPA, which builds upon the capabilities of the Spaceflight Secondary Payload System (SSPS) by incorporating propulsion and power generation subsystems, which creates a propulsive tug dedicated to maneuvering to an optimal orbit to place secondary and hosted payloads.
[8][9] D-Orbit, an Italian space logistics and transportation company, developed the InOrbit NOW ION Satellite Carrier.
[10] LDPE is based on a Northrop Grumman payload adapter used to help attach the upper stage to the main satellite in addition to hosting a few slots for other smallsats.
[13] Momentus Space became widely known in October 2020 when it reached a SPAC investment deal with Stable Road Acquisition Corp valuing the combined entity at over $1 billion.
[15] Launching on its own rocket as well as SpaceX’s Falcon 9 it provides 150 kilograms of payload, either 90 units of CubeSat or else larger satellites using standard smallsat separation systems.
[1] This, along with all other elements of STS except the Space Shuttle, was never funded after cutbacks to NASA's budget during the 1970s in the wake of the Apollo program.
[citation needed] A more powerful liquid hydrogen fueled Centaur-G stage was developed for use on the Shuttle, but was cancelled as too dangerous after the Challenger disaster.
The VASIMR electric plasma rocket could be used to power a high-efficiency space tug, using only 9 tons of Argon propellant to make a round trip to the Moon, delivering 34 tons of cargo from Low Earth Orbit to low lunar orbit.
As of 2014[update], Ad Astra Rocket Company had put forward a concept proposal to utilize the technology to make a space tug.
[26][needs update] ISRO has built an upper stage called PAM-G (Payload Assist Module for Geosynchronous Satellite Launch Vehicle) capable of pushing payloads directly to MEO or GEO orbits from low Earth orbits.
[27][28] PAM-G is powered by hypergolic liquid motor with restart capability, derived from Polar Satellite Launch Vehicle's fourth stage.
Lockheed Martin made a concept proposal to NASA in 2015 for a design called the Jupiter space tug, to be based on the designs of two earlier Lockheed Martin spacecraft—Mars Atmosphere and Volatile Evolution Mission and the Juno—as well as a robotic arm from MDA derived from technology used on Canadarm, the robotic arm technology previously used on the Space Shuttle.
Exoliner is based on the earlier (2000s) ESA-developed Automated Transfer Vehicle, and was to be jointly developed with Thales Alenia Space.
One of NASA's Artemis Program's proposed lunar landers is a partially reusable three stage design.
[49][50] Orbit fab is attempting to develop an in-space propellant supply chain aiming to provide 'Gas Stations in Space'.
A key component of FLARE is the modified ULA Common Centaur used as a SpaceTug to deliver an uncrewed human lander to lunar orbit and to assist NASA's Orion capsule returning crew to Earth [53] On October 9, 2024, Indian space startup Bellatrix Aerospace and NewSpace India Limited signed a contract for the integration of Pushpak Orbital Transfer Vehicles (OTV) for upcoming launch missions.
With the ability to move satellites into other orbits with more accuracy and efficiency, Pushpak OTV is made for in-orbit maneuvering.
