The pits, and caves to which they may lead, would make thermally stable sites for lunar exploration compared to areas at the Moon's surface, which heat up to about 127 Celsius during the day and cool to about minus 173 Celsius at night.
Lunar exploration is part of NASA's goal to explore and understand the unknown in space, to inspire and benefit humanity.
Pits were first discovered on the Moon in 2009, and since then, scientists have wondered if they led to caves that could be explored or used as shelters. The pits or caves would also offer some protection from cosmic rays, solar radiation and micrometeorites.
"About 16 of the more than 200 pits are probably collapsed lava tubes," said Tyler Horvath, a doctoral student in planetary science at the University of California in Los Angeles, who led the new research that was recently published in the journal Geophysical Research Letters.
"Lunar pits are a fascinating feature on the lunar surface," said LRO Project Scientist Noah Petro of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Knowing that they create a stable thermal environment helps us paint a picture of these unique lunar features and the prospect of one day exploring them."
Horvath processed data from Diviner, a thermal camera, to find out if the temperature within the pits diverged from those on the surface.
Focusing on a roughly cylindrical 100-metre deep depression which is about the length and width of a football field in an area of the Moon known as the Mare Tranquillitatis, Horvath and his colleagues used computer modelling to analyse the thermal properties of the rock and lunar dust and to chart the pit's temperatures over time.
The results revealed that temperatures within the permanently shadowed reaches of the pit fluctuate only slightly throughout the lunar day, remaining at around 17 Celsius. If a cave extends from the bottom of the pit, as images taken by LRO's Lunar Reconnaissance Orbiter Camera suggest, it too would have this relatively comfortable temperature.
The team believes the shadowing overhang is responsible for the steady temperature, limiting how hot things get during the day and preventing heat from radiating away at night.
A day on the Moon lasts about 15 Earth days, during which the surface is constantly bombarded by sunlight and is frequently hot enough to boil water. Brutally cold nights also last about 15 Earth days.
Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the Moon.
The US space agency conducted RS-25 single-engine Retrofit-2 test series at Stennis Space Center near Bay St Louis in Mississippi on Septemeber 30, the agency said in a statement.
"This successful test series for the Space Launch System RS-25 engine puts us one step closer to manufacturing the first new set of engines for future Artemis missions to the Moon," said Johnny Heflin, manager of the SLS liquid engines office at NASA's Marshall Space Flight Center in Huntsville, Alabama, in the statement.
"We are testing engine parts made with advanced manufacturing techniques that can reduce the cost of each engine by more than 30 per cent yet still maintain the RS-25 engine's reliability and high performance," Heflin added.
During the test, hot fire, operators fired RS-25 developmental engine No. 0528, used for each of the seven tests in the series, for more than eight minutes (500 seconds), the same time required during an actual launch.
The test series provided valuable information to Aerojet Rocketdyne -- lead contractor for the SLS engines -- as it produces engines for use after the Artemis IV mission to the Moon, NASA said.
Operators collected hot fire data to demonstrate and verify various engine capabilities, and to evaluate new engine components manufactured with cutting-edge and cost-saving technologies and reduce operational risk.
The test was initially delayed due to impacts from Hurricane Ida, which struck the Gulf Coast region on August 29.
NASA is building SLS as the world's most powerful rocket. Four RS-25 engines, along with a pair of solid rocket boosters, will help power SLS at launch. Firing simultaneously, the engines will generate a combined 1.6 million pounds of thrust at liftoff and 2 million pounds during ascent.
With Artemis, NASA will land the first woman and the first person of colour on the lunar surface and establish long-term exploration at the Moon in preparation for human missions to Mars.
SLS and the Orion spacecraft, along with the commercial human landing system and the Gateway in orbit around the Moon, are NASA's backbone for deep space exploration. The agency is working towards the launch of the Artemis I uncrewed flight test in upcoming months, which will pave the way for future missions.
The Indian Space Research Organisation (ISRO) is holding a two-day Lunar Science Workshop 2021, which began on Monday, to commemorate the completion of two years of operation of Chandrayaan-2 spacecraft around the lunar orbit.
In his inaugural address, ISRO Chairman, K Sivan said the eight payloads on board the Chandrayaan-2 spacecraft are conducting remote sensing and in-situ observations of the Moon at around 100 km altitude from the lunar surface.
"Till date, the Chandrayaan-2 has completed more than 9,000 orbits around the Moon," added Sivan, also Secretary in the Department of Space (DoS).
According to the Bengaluru-headquartered ISRO, data product and science documents were released by Sivan, along with data from Chandrayaan-2 orbiter payloads.
"The science data are being made available for analysis by academia and institutes, for a greater participation to bring out more science from Chandrayaan-2 mission," ISRO said.
Sivan said he has reviewed the science results, and found them to be "very much encouraging".
Chairman of Apex Science Board, ISRO, A S Kiran Kumar said the imaging and scientific instruments on board the Chandrayaan-2 satellite have been providing excellent data.
"Chandrayaan-2 has really incorporated many new features in its instruments which are taking the observations carried out on Chandrayaan-1 to a newer and higher level," added Kiran Kumar, a former ISRO Chairman.
Project Director of Chandrayaan-2, Vanitha M, said all the sub-systems of the orbiter were performing well.
"We hope that we can get good data from the spacecraft for many more years," she said.
Vanitha said the imaging payloads of the orbiter -- TMC-2 (Terrain Mapping Camera-2), IIRS (Imaging IR Spectrometer) and OHRC (Orbiter High Resolution Camera) have sent us breath-taking pictures of the Moon.
The two-day workshop, organised by ISRO, is being live-streamed on the space agency's website and Facebook page, for effectively reaching the students, academia and institutes, and to engage the scientific community to analyse Chandrayaan-2 data, an ISRO statement said.
The science results from the eight payloads are being presented by the scientists in the workshop being held virtually.
In addition, there will be lectures on the Chandrayaan-2 mission, tracking, operations, and data archival aspects.
Along with the scientists from ISRO/DoS, there will also be lectures on lunar science to be delivered by scientists from Indian Institute of Science Education and Research, Kolkata, Indian Institute of Science, Bengaluru, and Indian Institute of Technology, Roorkee, it was stated.
"The total budget of the moon mission is about Rs 450 crore, out of which we have raised more than half (Rs 225 crore) and have spent. We're trying to accumulate the rest through sponsors and others interested in this mission," TeamIndus Fleet Commander Rahul Narayan told reporters here on Thursday.
The firm aims to launch its spacecraft in three to six months in an attempt to win the "Google Lunar XPRIZE", a competition to challenge and inspire engineers and entrepreneurs from around the world to develop low-cost methods of robotic space exploration.
The state-run Indian Space Research Organisation (ISRO) will fly 600kg TeamIndus spacecraft (robot) on its PSLV (Polar Satellite Launch Vehicle) from its Sriharikota spaceport in Andhra Pradesh, about 80 km northeast of Chennai.
TeamIndus is the only Indian team among the five finalists competing for the $30 million Google Lunar XPRIZE.
This will be the first time ISRO has given a dedicated PSLV to any private entity. The deadline for the completion of the lunar mission set by Google Lunar XPRIZE is March 31, 2018.
The firm already has the backing of software giant Infosys' non-Executive Chairman Nandan Nilekani and Tata Group Chairman Ratan Tata among others and is mulling crowdfunding (raising money from large number of individuals putting in small amounts) to fund the mission.
"We are in talks with several people who have expressed their interest in the project and are hopeful of completing the mission," Narayan said.
As the Google Lunar XPRIZE judging panel were in the city on a five-day review of TeamIndus' moon mission plan, the chairman of the panel, Professor Alan Wells, said the team was in the "right trajectory to make history".
"We took a detailed look at the mission plan and the methodologies being employed to gauge the progress of the lunar mission. We have come away from this rigorous exercise impressed by the readiness of TeamIndus. They are clearly on the right trajectory to make history," Wells said.
To win the prize, privately-funded teams must land their spacecraft on the surface of the Moon, travel 500 metres, and broadcast high definition video and data back to Earth.
TeamIndus had signed a contract last year to carry a 4kg rover developed by Hakuto, the Japanese team that had also qualified for the finals of the competition.
The Indian firm is competing against SpaceIL (Israel), Moon Express (US), Synergy Moon (international) and Hakuto (Japan) in the competition.
The Bengaluru-based firm has over 100 engineers and 20 former ISRO scientists working on the spacecraft's design and technology.
The spacecraft is all set to leave the earth's orbit after two days, he told reporters here.
Sivan was on the city to take part in the birth centenary celebrations of Dr Vikram Sarabhai, regarded as the father of India's space programme.
The 3,850-kg Chandrayaan-2, a three-module spacecraft comprising orbiter, lander and rover, which was launched on July 22, would make a landing on the moon on September 7, the ISRO chief said.
"After launching Chandrayaan-2 on July 22, we did five maneuvers. The Chandrayaan-2 composite body is now revolving around the earth," he said.
The next very important and crucial maneuver will happen on Wednesday morning.
"At around 3.30 am on August 14, we are going to have a maneuver called trans-lunar injection. By this maneuver, the Chandrayaan-2 will leave the earth and move towards the moon.
On August 20, we will be reaching the moon," he said.
"Then, we will be carrying out lunar orbit insertion.
By this process, the Chandrayaan-2 will be around the moon on August 20. Subsequently, we have planned to have a series of maneuvers around the moon and finally on September 7, we will be landing on the moon near its south pole," he added.
Sivan said the spacecraft was "doing very well" at present and all its systems were functioning properly.
He said scientists at the ISRO will be busy in coming months, particularly in December when the space agency would take up a mission to launch small satellites.
"In December, we are going to have a very important mission. It's a small satellite launcher. This is for the first time we are going to have this mission," he said.
According to ISRO, the orbit manoeuvre began at 12.50 p.m. and took 1,228 seconds to complete. The orbit achieved is 118 km X 4,412 km.
All spacecraft parameters are normal.
The next Lunar bound orbit manoeuvre is scheduled on August 28, 2019 between 5.30 a.m. - 6.30 a.m.
On Tuesday, the Chandrayaan-2 was put into its first Lunar orbit.
On July 22, the Chandrayaan-2 was injected into an elliptical orbit of 170X45,475 km by India's heavy lift rocket Geosynchronous Satellite Launch Vehicle-Mark III (GSLV Mk III) in a text book style.
The spacecraft comprises three segments - the Orbiter (weighing 2,379 kg, eight payloads), the lander 'Vikram' (1,471 kg, four payloads) and rover 'Pragyan' (27 kg, two payloads).
The Indian space agency said the major activities include Earth-bound manoeuvres, the trans-lunar insertion, lunar-bound manoeuvres, Vikram's separation from Chandrayaan-2 and touch down on the Moon's South Pole.
According to Indian Space Research Organisation (ISRO), the spacecraft's maneuver began at 6.21 p.m. using its onboard propulsion system for 52 seconds.
The orbit achieved is 119 km x 127 km. All spacecraft parameters are normal.
The next crucial operation is the separation of Vikram, the lander, from the spacecraft scheduled on September 2 at 12.45 p.m. -1.45 p.m.
After Vikram's separation, there will be two de-orbital operations on September 3 and 4 so that it could soft land on the moon's south pole on September 7 at 1.30 a.m.- 2.30 a.m.
On July 22, the Rs 978 crore Chandrayaan-2 was launched into the space by India's heavy lift rocket Geosynchronous Satellite Launch Vehicle-Mark III (GSLV Mk III) in a text book style.
The spacecraft comprises three segments - the Orbiter (weighing 2,379 kg, eight payloads), the lander 'Vikram' (1,471 kg, four payloads) and rover 'Pragyan' (27 kg, two payloads).
In a statement, ISRO said: "The success criteria was defined for each and every phase of the mission and to date 90 to 95 per cent of the mission objectives have been accomplished and will continue to contribute to lunar science, notwithstanding the loss of communication with the Lander."
According to ISRO, the Vikram Lander followed the planned descent trajectory from its orbit of 35 km to just below 2 km above the surface.
"All the systems and sensors of the Lander functioned excellently until this point and proved many new technologies such as variable thrust propulsion technology used in the Lander," ISRO said.
The Indian space agency said the precise launch and mission management has ensured a long life of almost seven years for the Chandrayaan-2 Orbiter instead of the planned one year.
According to ISRO Chairman K.Sivan, the Orbiter has sufficient amount of fuel on-board for it to operate for seven years.
The ISRO said Chandrayaan-2 mission was a highly complex mission, which represented a significant technological leap compared to its previous missions.
The Chandrayaan-2 mission brought together an Orbiter, Lander and Rover to explore the unexplored south pole of the Moon.
Since the launch of Chandrayaan-2 on July 22, 2019, not only India but the whole world watched its progress from one phase to the next with great expectations and excitement.
"This was a unique mission which aimed at studying not just one area of the Moon but all the areas combining the exosphere, the surface as well as the sub-surface of the moon in a single mission," ISRO said.
"The Orbiter has already been placed in its intended orbit around the Moon and shall enrich our understanding of the Moon's evolution and mapping of the minerals and water molecules in the polar regions, using its eight state-of-the-art scientific instruments," the statement added.
The Orbiter camera is the highest resolution camera (0.3m) in any lunar mission so far and shall provide high resolution images which will be immensely useful to the global scientific community, ISRO added.
However, the statement is silent on the reason for the deviation in the Vikram's plotted descent chart which may not have to do with snapping of the communication link.
Only a photograph of the Vikram on the moon will tell whether it crash-landed.
Speaking to mediapersons at the Bhubaneswar airport, Sivan was happy to share that the Chandrayaan-2 orbiter is doing very well. He also said that the National level committee consisting of academicians and ISRO experts are analysing the cause of communication loss with the lander.
"Orbiter continues to perform scheduled science experiments to complete satisfaction. There are eight instruments in the orbiter and each instrument is doing exactly what it meant to do. Regarding the lander, we have not been able to establish communication with it yet. The scientists are trying to gauge the lapses, to see what exactly went wrong with Vikram lander. As soon as we avail any data, necessary steps will be taken subsequently."
He further said, "The orbiter was initially planned for a year, but with the optimum mission planning there is every possibility that it will last for another 7 and half years benefiting us for science experiments. Why we are saying Chandrayaan-2 achieved 98% success is because of two objectives- one is science and the other technology demonstration. In case of technology demonstration, the success percentage was almost full."
Speaking on the next mission, the ISRO chief said, "Our next priority is Gaganyaan mission, which will be the first unmanned mission. We have set a target of achieving this by the end of next year."
#Chandrayaan2 orbiter is doing very well. Each of the 8 instruments in the orbiter is doing exactly what we wanted. This mission was 98% successful. Our next priority is Gaganyaan: ISRO chief K Sivan after arriving at Bhubaneswar Airport #Odisha pic.twitter.com/4kVmUpwiOv
— OTV (@otvnews) September 21, 2019
Later in the day, Sivan attended the 8th Convocation ceremony of the Indian Institute of Technology (IIT), Bhubaneswar today as chief guest. Sivan addressed the students of IIT in the community centre of the institute at Argul, Jatni.
The Vikram lander module attempted a soft landing on a small patch of lunar highland smooth plains between Simpelius N and Manzinus C craters before losing communication with ISRO on September 7.
"Vikram had a hard landing and the precise location of the spacecraft in the lunar highlands has yet to be determined, NASA said.
The scene was captured from a Lunar Reconnaissance Orbiter Camera Quickmap fly-around of the targeted landing site image width is about 150 kilometres across the centre.
Vikram was scheduled to touch down on September. 7. This event was India's first attempt at a soft landing on the Moon. The site was located about 600 kilometres from the south pole in a relatively ancient terrain, according to the US space agency.
The LRO passed over the landing site on September 17 and acquired a set of high-resolution images of the area; so far the LROC team has not been able to locate or image the lander.
LRO will next fly over the landing site on October 14 when lighting conditions will be more favourable, John Keller, Deputy Project Scientist Lunar Reconnaissance Orbiter Mission, Goddard Space Flight Centre, told PTI via email.
"It was dusk when the landing area was imaged and thus large shadows covered much of the terrain; it is possible that the Vikram lander is hiding in a shadow. The lighting will be favourable when LRO passes over the site in October and once again attempts to locate and image the lander," NASA said.