Big Bang Observer
Proposed space observatory for early-universe gravitational waves.
The Big Bang Observer (BBO) is a proposed NASA space observatory (with ESA collaboration) designed to detect gravitational waves. Conceived as a follow-up to the Laser Interferometer Space Antenna (LISA), its main scientific aim is to capture gravitational waves originating from the era just after the Big Bang, though it would also pick up signals from younger sources such as binary inspirals. The observatory would achieve its extreme sensitivity through more powerful lasers and by correlating signals from multiple interferometers placed around the Sun, but it would not be sensitive to the same high-frequency range as LIGO, nor would it detect all LISA sources due to different design parameters.
The first phase of BBO resembles LISA, with three spacecraft arranged in a triangle. The second phase adds three more triangles—twelve spacecraft total—spaced 120° apart in solar orbit, with one position containing two overlapping triangles in a hexagram formation. The individual satellites differ from LISA’s by using far more powerful lasers, and each triangle has arm lengths of about 50,000 km (the distance between spacecraft) compared to LISA’s 1 to 5 million km. This smaller size means the test masses experience smaller tidal deviations, allowing them to be locked onto a specific interferometer fringe, similar to LIGO’s technique. In contrast, LISA’s test masses fly in nearly free orbits, with the spacecraft moving around them, and fringes are counted using a method called time-delay interferometry.
The BBO instruments pose massive technological challenges. No funding has been allocated for development, and even if selected, optimistic estimates place its launch many decades away.
- Field
- Gravitational wave astronomy
- Proposed by
- NASA (with ESA collaboration)
- Predecessor
- Laser Interferometer Space Antenna (LISA)
- Primary goal
- Observation of gravitational waves from shortly after the Big Bang
- Key technology
- Higher-power lasers and multiple interferometers
Lore & Background
The Big Bang Observer (BBO) is a proposed space observatory for gravitational waves by NASA (with ESA collaboration). A successor to the Laser Interferometer Space Antenna (LISA), its primary scientific goal would be the observation of gravitational waves from the time shortly after the Big Bang, but it would also be able to detect younger sources of gravitational radiation, like binary inspirals. BBO would not be sensitive to the same high-frequency range as LIGO, nor would it detect all LISA sources due to different design parameters. Its extreme sensitivity would come from the higher-power lasers, and correlation of signals from several different interferometers that would be placed around the Sun.
Reader's Guide
The Big Bang Observer represents a conceptual leap in gravitational wave astronomy, aiming to detect signals from the earliest moments after the Big Bang. Its proposed design, with twelve spacecraft in a hexagram formation and more powerful lasers than LISA, would achieve extreme sensitivity to gravitational waves from all LIGO and LISA sources and beyond. The technological challenges are massive, and funding has not been allocated for development; even if selected, optimistic estimates place its launch many decades away. Despite this, BBO's concept pushes the boundaries of what is possible in observing the universe through gravitational waves, offering a potential window into the primordial universe that no other planned observatory can reach. Its legacy lies in inspiring future missions and advancing the theoretical and engineering groundwork for ultra-sensitive space-based interferometry.
Did You Know?
- BBO would consist of twelve spacecraft in a hexagram formation, with one position having two overlapping triangles.
- Each triangle in BBO would have arm lengths of about 50,000 km (the distance between spacecraft), much smaller than LISA's 1 to 5 million km triangles.
- BBO's test masses could be locked on a particular interferometer fringe, unlike LISA's free-flying test masses.
- The BBO instruments present massive technological challenges and have not received development funding.
More in Space telescopes 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced