Distant retrograde orbit: Difference between revisions
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[[File:Orion Artemis I Selfie 1.jpg|thumb|Orion spacecraft prior to arriving at the Moon, where it would later get into DRO]] |
[[File:Orion Artemis I Selfie 1.jpg|thumb|Orion spacecraft prior to arriving at the Moon, where it would later get into DRO]] |
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On 16 November 2022, the [[Space Launch System]] was launched from Complex 39B as part of the [[Artemis 1]] mission carrying Orion to the moon.<ref>{{cite AV media |date=16 November 2022 |url=https://www.youtube.com/watch?v=CMLD0Lp0JBg |title=Artemis I Launch to the Moon (Official NASA Broadcast) - Nov. 16, 2022 |publisher=[[NASA]] |via=[[YouTube]] |access-date=2 December 2022 |archive-url=https://web.archive. |
On 16 November 2022, the [[Space Launch System]] was launched from Complex 39B as part of the [[Artemis 1]] mission carrying Orion to the moon.<ref>{{cite AV media |date=16 November 2022 |url=https://www.youtube.com/watch?v=CMLD0Lp0JBg |title=Artemis I Launch to the Moon (Official NASA Broadcast) - Nov. 16, 2022 |publisher=[[NASA]] |via=[[YouTube]] |access-date=2 December 2022 |archive-url=https://web.archive.org/web/20221129101304/https://www.youtube.com/watch?v=CMLD0Lp0JBg |archive-date=29 November 2022 |url-status=live}}</ref><ref name="nasa-20221108">{{cite web |url=https://blogs.nasa.gov/artemis/2022/11/08/nasa-prepares-rocket-spacecraft-ahead-of-tropical-storm-nicole-re-targets-launch/ |title=NASA Prepares Rocket, Spacecraft Ahead of Tropical Storm Nicole, Re-targets Launch |author=[[NASA]] |date=8 November 2022 |access-date=8 November 2022}}</ref> On 25 November it entered DRO and will spend between half and one and a half orbital periods in that orbit.<ref name="Nov15">{{cite web |date=27 November 2015 |title=The Ins and Outs of NASA's First Launch of SLS and Orion |url=http://www.nasa.gov/feature/the-ins-and-outs-of-nasa-s-first-launch-of-sls-and-orion |access-date=3 May 2016 |author=[[NASA]] |archive-date=22 February 2020 |archive-url=https://web.archive.org/web/20200222201819/https://www.nasa.gov/feature/the-ins-and-outs-of-nasa-s-first-launch-of-sls-and-orion |url-status=live }} {{PD-notice}}</ref><ref>{{Cite web |last=Foust |first=Jeff |date=2022-11-25 |title=Orion enters lunar distant retrograde orbit |url=https://spacenews.com/orion-enters-lunar-distant-retrograde-orbit/ |access-date=2022-11-29 |website=SpaceNews |language=en-US}}</ref> |
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== Space concepts proposed to use a DRO == |
== Space concepts proposed to use a DRO == |
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Revision as of 15:58, 3 December 2022
A distant retrograde orbit (DRO), as most commonly conceived, is a spacecraft orbit around a moon that is highly stable because of its interactions with two Lagrange points (L1 and L2) of the planet–moon system.
In more general terms, an object of negligible mass can be in a DRO around the smaller body of any two-body system, such as planet–Sun or exoplanet–star.
Using the example of a spacecraft in a DRO around a moon, the craft would orbit in the direction opposite to the direction in which the moon orbits the planet. The orbit is "distant" in the sense that it passes above the Lagrange points, rather than being near the moon. If we consider more and more distant orbits, the synodic period (the period between two moments when the craft passes between the planet and the moon) gets longer and approaches that of the moon going around the planet, so that the sidereal period (the time it takes for the craft to come back to a given constellation as viewed from the moon) can become much longer than the orbital period of the moon. A hypothetical example with Europa has a sidereal period about eight times the orbital period of Europa.[1]
DROs have been researched for several decades, but in 2022, NASA's Orion Spacecraft entered the orbit during the Artemis 1 mission and it was speculated that the Chang'e 5 orbiter may also have now done so.[2]
Description
The stability of a DRO is defined in mathematical terms as having very high Lyapunov stability, where an equilibrium orbit is "locally stable if all solutions which start near the point remain near that point for all time".[1]
List of objects in distant retrograde orbit
Chang'e 5 orbiter
China's Chang'e 5 (CE-5) orbiter, which according to The Space Review (TSR) may have moved to a lunar DRO by January 2022, could be conducting very-long-baseline interferometry tests to support Chinese preparations for the next stage of China's Lunar Exploration Program. The analysis by TSR was based on statements made by Chinese government information and Chinese academics.[2][needs update] If the move to DRO was actually made, then Chang'e 5 would be the first spacecraft to actually enter a DRO to test the theoretical result.
Orion spacecraft
On 16 November 2022, the Space Launch System was launched from Complex 39B as part of the Artemis 1 mission carrying Orion to the moon.[3][4] On 25 November it entered DRO and will spend between half and one and a half orbital periods in that orbit.[5][6]
Space concepts proposed to use a DRO
Jupiter Icy Moons Orbiter
A distant retrograde orbit was one of the proposed orbits around Europa for the Jupiter Icy Moons Orbiter—principally for its projected stability and low-energy transfer characteristics—but that mission concept was cancelled in 2005.[1]
Asteroid Redirect Mission (ARM)
A distant retrograde orbit was considered to be used for the proposed Asteroid Redirect Mission. Although the mission would end up getting cancelled, the research done with DRO in-mind, lead to the orbit being used for Artemis 1.[7]
NASA Lunar Gateway
Two system requirements for the NASA Lunar Gateway, as published in the Baseline DSG-RQMT-001[8] published in June 2019, mention the use of lunar DROs. Requirement L2-GW-0029, Single Orbit Transfer, states "the Gateway shall be capable of performing a single round trip transfer to Distant Retrograde Orbit (DRO) and back within 11 months". Requirement L2-GW-0026, Propulsion System Capability, states "the Gateway shall provide a fuel capacity that would support performing a minimum of two round-trip uncrewed low-energy cislunar orbit transfers between a near-rectilinear halo orbit (NRHO) and a distant retrograde orbit (DRO) and orbit maintenance for a period of 15 years between refueling". Although the selected orbit for the Gateway has been confirmed to be NRHO[9] instead of DRO.
DRO orbits in fiction
In the 2019 Daniel Suarez novel Delta-v, a 560-tonne crewed asteroid-mining ship Konstantin is constructed in a lunar DRO approximately 40,000 km (25,000 mi) above the Moon.[10]
See also
References
- ^ a b c Johnson, Kirstyn (18 December 2014). "Understanding NASA's Asteroid Redirect Mission: Distant Retrograde Orbits". Archived from the original on 11 January 2015. Retrieved 3 May 2015.
- ^ a b Burke, Kristin (11 April 2022). "The Space Review: What is China doing at the lunar distant retrograde orbit?". The Space Review. Archived from the original on 2022-04-12. Retrieved 2022-04-12.
- ^ Artemis I Launch to the Moon (Official NASA Broadcast) - Nov. 16, 2022. NASA. 16 November 2022. Archived from the original on 29 November 2022. Retrieved 2 December 2022 – via YouTube.
- ^ NASA (8 November 2022). "NASA Prepares Rocket, Spacecraft Ahead of Tropical Storm Nicole, Re-targets Launch". Retrieved 8 November 2022.
- ^ NASA (27 November 2015). "The Ins and Outs of NASA's First Launch of SLS and Orion". Archived from the original on 22 February 2020. Retrieved 3 May 2016.
This article incorporates text from this source, which is in the public domain.
- ^ Foust, Jeff (2022-11-25). "Orion enters lunar distant retrograde orbit". SpaceNews. Retrieved 2022-11-29.
- ^ NASA [@NASA] (19 November 2022). "@JVendl @NASA_Orion We first studied the DRO to support the proposed Asteroid Redirect Mission (ARM) which paralleled early SLS and Orion development. The plan for ARM was to capture a near Earth asteroid and redirect it to a lunar DRO. (1/4)" (Tweet). Retrieved 2 December 2022 – via Twitter.
- ^ NASA (2019). "DSG-RQMT-001 – Gateway Program System Requirements Document (SRD)" (PDF). NASA Technical Reports Server. p. 25. Archived (PDF) from the original on 11 April 2020. Retrieved 11 April 2020.
- ^ Zaid, Christina (2022-05-16). "A unique halo orbit is the road less traveled around the Moon". NASA. Retrieved 2022-11-29.
- ^ Suarez, Daniel (2019). Delta-v. New York: Penguin Random House. pp. 189–198. ISBN 978-1524742416.
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