The Future of Space Observations
The space industry is in the midst of a data revolution. The two key trends causing this include data proliferation and commercialization. This is interesting because both scientists and commercial players are participants in this change. The rise of petabyte size data releases and privatization of data will forever change how space observations are made and used.
The proliferation of astronomical data has generally followed Moore's law of transistor count doubling every two years. More astronomical data is generated when more advanced instruments are used and there is a greater ability to transmit, process, and store that data.
In 1994, the Digitized Sky Survey digitized photographic plates, whose compressed files used about 600 gigabytes of storage. The first data release from the Sloan Digital Sky Survey (SDSS) in 2004 was about 3 terabytes (3000 gigabytes). Last week, the Pan-STARRS sky survey set a record for the largest astronomical data release ever when it released its second collection totaling 1.6 petabytes (1.6 million gigabytes) of data.
These data releases provide many years worth of data, so a more apt comparison is based on data collected per night. The SDSS collects about 200 gigabytes of data a night. As large as that is, the upcoming Large Synoptic Survey Telescope (LSST) is expected to produce 15 terabytes of data per night when it starts operation in 2022.
Besides the large amount of data modern sky surveys produce, their defining feature is collecting temporal data. That is, they observe snapshots of the same patch of sky over time. This allows scientists to determine what has changed in the sky, even with tiny changes. Changes include supernovae explosions, variable stars, transiting exoplanets, and asteroid movements.
The other large shift in astronomical data is the rise of non-governmental groups wanting to accelerate the collection of data, albeit with data restrictions. To a degree, this approach has existing since the start of observation programs. Universities invested in the hardware and expertise, and kept the observation results within their archives.
Modern collaboration programs typically encompass a few universities or research groups, and provide funding for large observation projects. In return for the investment, they usually restrict data access for a few years before releasing the data under varying terms. This exclusivity period allows collaborating scientist time to perform their work without having their work sniped from others.
In an attempt to encourage science, many collaborations release the data for other scientists to study and analyze. The idea is that collaborating scientists have specific goals in mind, but outside scientists have their own unique ideas in how to analyze the data. Ultimately, opening up data to the scientific community yields new discoveries the original collaboration could have never envisioned.
Generally, this structure works out well for the backing collaboration. They are able to realize a return on their investment, while also benefiting the greater scientific community after a few years.
Government funded observation programs can complicate the approach of exclusive data. This is especially true in the United States, where Freedom of Information requests have been used to access exclusive data early. Basically, things get complicated when public funds are used to generate exclusive data that is not classified.
Other approaches for astronomical data include making the data publicly accessible immediately after normal verification. The LSST will be one of the few large observation programs that will do this. Some programs that monitor for highly transient events also follow an approach like this, where time is critical.
New collaborations, such as the Milo Institute, are planning to develop and operate custom spacecraft for a member only observation programs. This follows the approach of modern collaborations, where members can access data exclusively for a few years. This collaboration is unique because they will develop and operate non-governmental deep-space spacecraft. Their current goal is to perform in-situ observations of a few near-Earth objects.
Collaborations like Milo promise to accelerate the data collection process, minimizing reliance on large decadal projects. Essentially, this allows scientists to develop highly targeted and dedicated missions to collect the data they need. Instead of putting everything and the kitchen sink in the mission, they are building mission specific vehicles.
Other proposed groups may restrict their data indefinitely. Restricting astronomical data will be tied to space resource exploration. A good analogy is how terrestrial resource surveys are restricted. Knowledge of where resources are is valuable information. There are likely commercial groups exploring the business case for collecting proprietary lunar or asteroid data, and selling access to it. Planet is a good example of this, where they use their private Earth observation constellation to collect data, and then sell access to analytics using that data.
One of the main sales pitches for commercial lunar landing firms is delivery of scientific equipment to the lunar surface. This is likely to follow one of the approaches above, where data is either publicly available, time restricted, or forever private.
The rise of low cost missions to asteroids or the Moon are changing the math of how astronomical data is acquired and distributed. This is a good thing because the more we understand these objects, the better our collective knowledge of our celestial backyard.
We are in an exciting phase of astronomy and space exploration. The rapid technological innovations occurring with smaller hardware is allowing the rise of data sets that are astronomical in size, while also allowing smaller groups to build and operate spacecraft to gather targeted observations themselves. Data will likely be an early commodity of the space economy, but given time, information wants to be free.
Postman, M. "Availability of the Digitized Sky Survey on CD-ROMs." IAU Commission on Instruments 5 (1994): 53.