Constellation program

The Constellation program was a plan by NASA, the space agency of the United States, to send astronauts on new adventures from 2005 to 2009. The main goals were to finish work on the International Space Station and to send people to the Moon by 2020. The biggest dream was to one day travel to the planet Mars.

The program started after President George W. Bush shared his ideas for space exploration. NASA created new plans to reach these goals, and began building rockets and spacecraft for trips to the Moon and Mars. The program's name and symbols were inspired by the planet Mars, using the name of its rockets, Ares.

In 2009, a review showed that the Constellation program would need much more money to work. In 2010, President Barack Obama decided to cancel the program. NASA then started working on new plans, like the Space Launch System, for future space missions.

Designs

One of the main goals of Constellation was to create new spacecraft and rockets to replace the Space Shuttle. NASA had already started designing two rockets, the Ares I and Ares V, when the program began. Ares I was made just to carry people into space, while Ares V was meant for heavier loads.

NASA also designed other spacecraft for Constellation, including the Orion crew capsule, the Earth Departure Stage rocket part, and the Altair moon lander.

Vehicles

Orion

The Orion spacecraft was made for the Constellation program to carry people in space. Lockheed Martin was chosen to build Orion, and Boeing would make its heat shield. NASA planned different versions of Orion for different missions. The Block I Orion would fly to the International Space Station, while Block II and III would be for deeper space travel.

Orion has three main parts: a crew module for people, a service module with engines and supplies, and a Launch Abort System to keep astronauts safe if problems happen during launch. The Crew Module could be used again. Even though Constellation was stopped, Orion kept being built. It flew its first test in 2014 and joined missions in 2022 and 2026.

Altair

Altair, also called the Lunar Surface Access Module, was meant to carry astronauts to the Moon. It was much bigger than the Apollo Lunar Module, almost five times larger. It was about 32 feet tall and 49 feet wide.

Altair had two parts: an ascent stage for the crew and a descent stage for landing and holding supplies and equipment. It was designed to land near the Moon's poles, a good spot for future moon bases. Altair would not be reused after each trip.

The descent stage would use special rocket engines, and the ascent stage would use one main engine to fly back. There was also a chance it would use different engines for the trip.

Propulsion

NASA wanted to use two different rockets for Constellation: Ares I for people and Ares V for cargo. This let each rocket be best for its job. The name Ares comes from Mars, the goal of future missions. The numbers I and V honor the Saturn rockets from the 1960s.

Ares I

The Ares I rocket would launch Orion into space. It used a Solid Rocket Booster and a liquid-fueled second stage with a J-2X engine. NASA chose Ares I for its safety, reliability, and cost savings.

NASA tested parts of Ares I and launched a test flight called Ares I-X in 2009 before the program ended.

Ares V

Ares V could carry much more than the Space Shuttle or Saturn V. It would use six RS-68 engines and two Solid Rocket Boosters. Later, NASA thought about using different engines because of heat issues.

Earth Departure Stage

The Earth Departure Stage was meant to send Altair toward the Moon from space. Orion would launch separately on Ares I and meet up with Altair after Ares V launched. This way, the crew could get to the Moon.

Comparison to Apollo and Space Shuttle designs

NASA wanted to use Constellation vehicles for jobs the Space Shuttle used to do. Constellation used ideas from both Apollo and the Space Shuttle.

Orion looks like Apollo's command module but uses newer technology. Ares I used many Apollo ideas. The J-2X engine for Ares V was first planned like Apollo's J-2 engine, but later got a new design.

Like Apollo, Constellation would have used lunar orbit rendezvous. But it would also use Earth orbit rendezvous to get the crew to the vehicle. Altair would launch on Ares V, and Orion would launch separately. Orion would stay uncrewed in lunar orbit while everyone landed on the Moon. Later, Altair would join Orion in lunar orbit, and Orion would return to Earth.

Missions

Main article: List of Constellation missions

The Constellation program aimed to send astronauts into space using the Orion spacecraft. Missions would include flying to the International Space Station to help build and support it, and planning trips to the Moon with the Altair and Earth Departure Stage vehicles. Though the program had big dreams like sending people to Mars, there were no detailed plans for a Mars trip when the program ended. There was some early thinking about visiting an asteroid near Earth as well.

International Space Station and low-Earth orbit flights

See also: Low Earth orbit

Parts of the Ares I and Orion spacecraft would be built in factories and then tested and put together at the Vehicle Assembly Building at the Kennedy Space Center. After everything was ready, the spacecraft would be moved to a special launch pad.

The crew would get into their spacesuits three hours before launch. After safety checks, the Ares I rocket would blast off. After two days, the Orion spacecraft would meet up with the International Space Station. Up to six astronauts would visit the station for tasks, staying for about six months but possibly shorter or longer depending on the mission. When their time was up, they would return to Earth in the Orion, which could splash down in the ocean and be used again up to ten times.

Lunar sortie flights

See also: Lunar sortie and NASA lunar outpost concepts

Instead of launching everything together like in the Apollo missions, the Orion spacecraft and the lunar lander called Altair would fly separately. The Altair and its rocket would launch first, followed about 90 minutes later by the crew in Orion. The two would meet in orbit and head to the Moon. After orbiting the Moon, the astronauts would land in Altair, explore the surface, and then return to Orion to head back to Earth.

Orion asteroid mission

For the asteroid visit mission superseding the corresponding Constellation program mission, see Asteroid Redirect Mission

There was a plan to send Orion to a near-Earth asteroid. The mission would use Orion and a special landing module based on Altair. The crew would study the asteroid, test ways to get resources from it, and look at ways to protect Earth from asteroid impacts. This would be the first time humans visited a place besides the Moon.

The mission would start like a Moon trip, with the landing module and Orion launching separately. After meeting up, they would head to the asteroid, land, explore, and then return to Earth.

Orion Mars mission

The ultimate goal of NASA's Constellation program was a crewed mission landing humans on Mars in the 2030s as a spiritual successor to the Apollo Applications Program in the 1960s. The mission would utilize the hardware of the Constellation Project, primarily the Orion spacecraft (or a variation based on the Orion), and the Ares V cargo-launch vehicle.

Justification for a return to the Moon

NASA lists a number of reasons for a human return to the Moon on its website:

1. to extend human colonization,
2. to further pursue scientific activities intrinsic to the Moon,
3. to test new technologies, systems, flight operations and techniques to serve future space exploration missions,
4. to provide a challenging, shared and peaceful activity to unite nations in pursuit of common objectives,
5. to expand the economic sphere while conducting research activities that benefit our home planet,
6. to engage the public and students to help develop the high-technology workforce that will be required to address the challenges of tomorrow.

In the words of former NASA Administrator, Michael D. Griffin, "The goal isn't just scientific exploration.... It's also about extending the range of human habitat out from Earth into the Solar System as we go forward in time.... In the long run a single-planet species will not survive.... If we humans want to survive for hundreds of thousands or millions of years, we must ultimately populate other planets ... colonize the Solar System and one day go beyond."

A report published in June 2014 by the US National Academy of Sciences called for clear long-term space goals at NASA. The report said that the agency's current course invited "failure, disillusionment, and [loss of] the longstanding international perception that human space-flight is something that the United States does best." The report recommended that Mars be the next major goal of human space flight. Several possible paths for reaching the planet by 2037 were explored in the report, which noted that returning to the Moon would offer "significant advantages" as an intermediate step in the process.

The National Space Society (NSS), a private nonprofit, regards a return to the Moon as a high priority for the US space program, in order to develop the body of scientific knowledge of the Moon, particularly in regards to its potential for the creation of new industries, in order to provide further funding for further space exploration.

Budget and cancellation

Bush administration

On January 14, 2004, President George W. Bush asked NASA to create a plan for more human space travel after finishing the International Space Station and retiring the Space Shuttle in 2010. The plan aimed to set up a long-term human presence on the Moon to make future space missions cheaper. This would include using lunar soil to make rocket fuel or air to breathe. The experience gained could help develop new technologies for long-term space exploration.

NASA estimated the original plan would cost $230 billion (in 2004 dollars) through 2025, but technical challenges made it hard to give a clear cost estimate.

Obama administration

When he took office, President Obama said the Constellation program was "over budget, behind schedule, and lacking in innovation." A review found it would cost about $150 billion to meet its goals under the original timeline. Another review in 2009, ordered by President Obama, showed that returning to the Moon or sending people to Mars was not possible with NASA's current budget. The Augustine panel suggested different options, including two main goals (the Moon and deep space), three types of Super Heavy Launch vehicles, and a strong research program including work on propellant depots.

After looking at the report and talking to Congress, the Obama administration decided not to include Constellation in the 2011 United States federal budget. On February 1, 2010, the President's budget proposal came out with no funding for the project, and it became law on April 15, 2011.

President Obama held a Space Conference on April 15, 2010, in Florida. At the conference, he and space leaders talked about the future of U.S. human spaceflight and announced a new plan based on the Augustine Panel's "Flexible Path to Mars" option. This plan kept working on the Orion capsule to help the ISS and set 2015 as the deadline for designing a new Super Heavy Launch Vehicle. In October 2010, the NASA authorization bill for 2010 was signed into law, canceling Constellation. However, earlier laws kept Constellation contracts active until new funding was approved in 2011.

Commercial Crew Vehicles and the Artemis program

NASA keeps working on the Orion spacecraft for deep space travel. To save money, NASA hired private companies to build vehicles for trips in low Earth orbit. Since May 2020, the Commercial Crew Development program has used SpaceX's Crew Dragon to carry people to and from the International Space Station, and Boeing's Starliner started doing the same in 2024. NASA also wants to make sure the launch vehicles in the United States Air Force Evolved Expendable Launch Vehicles program are safe for people. Private spacecraft also help carry cargo to the ISS under the Commercial Resupply Services program.

The Orion spacecraft and Ares V (also part of the Jupiter DIRECT family of rockets) were changed and approved again in 2010/2011 to be the main payload of the Space Launch System, and the program was partly brought back as the Artemis program in 2017.