The Last Destination Is Looking Outward
Every module before this one aimed at a place — Earth orbit, the Moon, Mars, the outer planets. This one aims a telescope at everything else, and closes both SSA-05 and the whole five-course sequence this site has been building since SSA-01.
Ground vs. Space
Ground-Based
Cheaper, Bigger, Limited
Far cheaper to build, maintain, and upgrade, with room for much larger mirrors. But Earth's atmosphere blurs and distorts incoming light (adaptive optics helps, but imperfectly) and blocks most infrared, ultraviolet, X-ray, and gamma-ray wavelengths outright.
Space-Based
Clear, Expensive, Fixed
No atmosphere to distort or block anything — entire wavelength ranges become observable for the first time. But cost, and Module 1's mass budget, cap how large a mirror can launch at all, and repair is rarely an option once it's in orbit.
Hubble vs. JWST
Both solved "repair is rarely an option" completely differently — one by design, one by refusing to accept the limitation.
Hubble Space Telescope
Since 1990, LEO, Serviceable
Observes visible, ultraviolet, and near-infrared light from low Earth orbit — close enough that Space Shuttle astronauts serviced it five separate times (SSA-02 Module 5's EVA content, Module 7's servicing thread), repairing and upgrading it well past its original planned lifespan.
James Webb Space Telescope
Since 2021, L2, Not Serviceable
An infrared specialist positioned at Sun-Earth L2 (SSA-01 Module 2's Lagrange points) — far too distant for any crewed servicing mission, so it was built assuming zero repair opportunities ever. Its infrared sensitivity lets it see further back in time and deeper into dust-obscured star formation than Hubble ever could.
What's Next
Next-generation space telescopes, further lunar and Mars missions, additional outer-planet and small-body targets — every destination this course covered has real planned or proposed follow-on missions in development right now. This is, by the syllabus's own design, the single most time-sensitive part of the entire curriculum: treat any specific mission name or date here as a snapshot of what was planned when this was written, not a fixed roster, and check current mission pages before relying on anything specific.
Looking Back
This is the last module in the curriculum. Here's the shape of what it actually built, course by course.
SSA-01 — Introduction to Space Studies
The broad survey — astronautics, astronomy, policy, economics, and exploration as one interdisciplinary field, not four separate ones.
SSA-02 — Introduction to Space Flight
The engineering underneath the survey — propulsion, launch vehicles, orbital mechanics, applied satellites, and what it takes to keep a human being alive up there.
SSA-03 — History of Space Flight
The same technology and the same people, traced chronologically — deliberately treated as history with real causes and real costs, not a triumph narrative.
SSA-04 — Space Policy
The rules governing all of it, and — deliberately, every single time — who those rules structurally benefit, with the competing positions stated fairly and no verdict handed down.
SSA-05 — Planetary and Space Exploration
Everything else applied to an actual destination — the physics, the history, and the policy, all aimed at the Moon, Mars, the outer planets, and now, here, the instruments looking past all of them.
Key Terms
- Adaptive Optics
- A technology that rapidly deforms a telescope's mirror to partially correct for atmospheric distortion — helpful for ground-based telescopes, but not a full substitute for observing from space.
- Atmospheric Absorption
- Earth's atmosphere blocking most infrared, ultraviolet, X-ray, and gamma-ray light before it ever reaches the ground — the core reason certain observations require a space-based telescope.
- Servicing Mission
- A crewed mission to repair or upgrade a spacecraft already in orbit — Hubble was serviced five times this way; JWST was built assuming this would never be possible.
For This Module
NASA Hubble and JWST public mission pages, ESA and STScI public astronomy education materials, and NASA's multi-mission overview pages for planned and proposed future missions. This module should always be checked for current developments before publishing — it's the most time-sensitive part of the entire curriculum.
SSA-05 Complete — And the Curriculum With It
All eight modules of SSA-05 are published, closing five full courses built from primary sources rather than paraphrased summaries. Start over from the beginning, or revisit any course along the way.