Cosmos Daily

Category: Spaceflight

  • Inside Artemis: How Humanity Plans to Return to the Moon

    Inside Artemis: How Humanity Plans to Return to the Moon

    More than half a century after the last Apollo crew left the lunar surface, NASA’s Artemis program is working to put astronauts back on the Moon — this time with the goal of staying. Artemis is not a single rocket or a single landing. It is a stack of interlocking systems, international partnerships, and commercial contracts, all pointed at a region no crew has ever visited: the lunar south pole.

    The hardware at the core

    Three pieces of hardware do the heavy lifting. The Space Launch System is a heavy-lift rocket built around a core stage derived from Space Shuttle main engine technology, flanked by a pair of solid rocket boosters. Riding on top is Orion, a crew capsule designed for deep space rather than low Earth orbit, with a European Service Module supplying power, propulsion, and life support.

    Neither of those can land. That job falls to a Human Landing System, procured commercially rather than built in-house — a significant departure from the Apollo model, where NASA owned the whole vehicle. The lander meets Orion in lunar orbit, carries the crew down to the surface, and brings them back up.

    Why the south pole

    Apollo landed near the lunar equator, in sunlit terrain that was relatively easy to reach and navigate. Artemis is aiming somewhere far more awkward, and for a good reason: water.

    The Moon’s axis is tilted only slightly, which means the floors of some polar craters have not seen sunlight in billions of years. Those permanently shadowed regions act as cold traps, and orbital data has consistently pointed to water ice accumulating inside them. Ice is drinking water, breathable oxygen, and — split into hydrogen and oxygen — rocket propellant. A base that can manufacture its own consumables is far cheaper to sustain than one supplied entirely from Earth.

    The difference between Apollo and Artemis is the difference between visiting and moving in.

    The polar region also offers ridges and crater rims that receive near-continuous sunlight, which matters enormously for solar power and for surviving the two-week lunar night.

    The step-by-step plan

    Artemis is deliberately sequenced, with each mission retiring risk for the next.

    • An uncrewed test flight sent Orion around the Moon and back to validate the capsule, its heat shield, and the SLS launch system.
    • A crewed flight follows the same broad trajectory with astronauts aboard, testing life support and deep-space operations without attempting a landing.
    • A subsequent mission carries a crew to lunar orbit, transfers them to a lander, and puts boots on the surface near the south pole.
    • Later missions add infrastructure: a small station in lunar orbit, surface mobility, and eventually habitats designed for longer stays.

    Gateway and the long game

    Gateway is the piece that most clearly signals long-term intent. It is a compact space station planned for a highly elliptical near-rectilinear halo orbit around the Moon — an orbit chosen because it is stable, energy-efficient to reach, and offers continuous communication with Earth.

    Gateway is not a destination in itself. It is a staging post: somewhere landers can dock, crews can transfer, and science payloads can operate between surface expeditions. It is also the most international element of the program, with modules and contributions from European, Japanese, and Canadian agencies.

    What could slow it down

    Ambitious programs slip, and Artemis has been no exception. The landing system, the new spacesuits, and the orbital refueling techniques that some lander architectures require are all genuinely hard engineering problems being solved in parallel. Schedules have moved more than once, and they may move again.

    That is worth stating plainly rather than glossing over. But the underlying shift is real: the Moon is being approached this time as a place to work rather than a place to visit, with reusable elements, commercial partners, and a target region chosen for its resources rather than its convenience.

    If Artemis succeeds on its own terms, the milestone will not be a single set of footprints. It will be the second crew arriving, and finding the lights already on.

  • Reusable Rockets: How Landing Boosters Changed Spaceflight

    Reusable Rockets: How Landing Boosters Changed Spaceflight

    For the first six decades of spaceflight, the standard practice was to build an enormously complex machine, use it once, and let it fall into the ocean. The reasoning was not stupidity. It was that recovering and reusing a booster costs performance, weight, and development money, and nobody had demonstrated that the savings would outweigh the costs.

    That assumption has now been tested, and the answer changed the industry.

    Why reuse is hard

    A rocket first stage is a thin-walled tank containing enormous quantities of propellant, structurally optimised to the edge of what will survive flight. After separation it is travelling at thousands of kilometres per hour, tens of kilometres up, with essentially no aerodynamic control and no reason to stay intact.

    Bringing it back means solving several problems at once:

    • Reversing its motion, which requires holding back propellant that could otherwise have gone toward payload.
    • Surviving re-entry heating on a structure never designed as a re-entry vehicle.
    • Controlling attitude in thin air where conventional fins do little.
    • Slowing from supersonic speed to a standstill and landing on a target measured in metres.
    • Doing all of this while leaving the engines in a condition that permits reflight without a rebuild.

    The Space Shuttle is the cautionary example. It was reusable in principle, and it did fly its orbiters repeatedly. But the refurbishment between flights was so labour-intensive, and the system so complex, that the promised cost savings never materialised. Reusability alone is not the goal. Rapid, cheap reusability is.

    What made it work

    Propulsive landing turned out to be the tractable approach, and several developments converged to make it practical.

    Engines had to become deeply throttleable and restartable in flight, which is a substantial demand on turbomachinery and ignition systems. Grid fins provided aerodynamic control authority during descent. Cold-gas thrusters handled attitude control outside the atmosphere. And crucially, guidance software became good enough to compute a landing trajectory in real time, correcting continuously as conditions changed.

    The last point is easy to underrate. The precision required to land a booster on a small barge in the ocean is not primarily a hardware achievement. It is a control problem that was not solvable with the computing available in the 1970s.

    The physics of landing a booster was never in doubt. The economics and the control software were.

    What it changed

    The visible effect is on price per kilogram to orbit, which has fallen substantially. The less visible effects may matter more.

    Launch cadence rose dramatically. When a booster can be recovered and flown again within weeks, the bottleneck shifts from manufacturing to processing, and the number of flights per year climbs into territory that was previously implausible.

    That cadence enabled business models that did not previously make sense. Large satellite constellations — hundreds or thousands of spacecraft — require a launch rate that expendable rockets could not economically supply. Rideshare missions became routine, giving small operators and universities affordable access to orbit.

    It also changed how hardware is developed. When flights are cheap and frequent, testing in flight becomes a reasonable engineering strategy rather than an unacceptable risk. Iterating on real vehicles is faster than iterating on simulations.

    What remains unsolved

    Reuse today is mostly partial. First stages are recovered; upper stages generally are not, because an upper stage reaches orbital velocity and must survive a full re-entry to come back. That is a much harder thermal problem, and solving it is the current frontier.

    Fairings — the protective nose cone — are also recovered in some systems, though they are a smaller share of vehicle cost.

    Full and rapid reuse of an entire launch vehicle, with turnaround measured in hours rather than weeks, remains a goal rather than a demonstrated capability. Whether it is achievable at scale is the open question that will determine how much further launch costs can fall.

    The wider shift

    Reusability arrived alongside a broader change in how spaceflight is procured. Agencies increasingly buy launch services rather than build launch vehicles, competing suppliers against each other rather than funding a single national system on a cost-plus basis.

    The two developments reinforce each other. Fixed-price competition creates pressure to reduce cost; reusability is the most effective available lever. Landing boosters became normal remarkably quickly — the first successful landings were genuinely startling, and within a few years they had become a routine footnote at the end of a launch broadcast.

  • Life Aboard the International Space Station

    Life Aboard the International Space Station

    The International Space Station has been continuously inhabited since November 2000. Somebody has been off the planet every day for a quarter of a century.

    It is roughly the size of a football field, circles Earth about every ninety minutes, and travels at around 28,000 kilometres per hour. From the inside, none of that is what defines the experience. What defines it is that nothing stays where you put it.

    Freefall, not zero gravity

    The station is not beyond Earth’s gravity. At its altitude of roughly 400 kilometres, gravity is still about ninety percent as strong as at the surface.

    What produces weightlessness is that the station and everything inside it are falling continuously, and moving sideways fast enough that the ground curves away beneath them at the same rate. Orbit is not the absence of falling. It is falling and missing.

    The correct term is microgravity, since small residual accelerations remain from atmospheric drag, equipment vibration, and crew movement. For sensitive experiments, those tiny forces matter.

    What the body does about it

    Human physiology assumes a downward direction, and removing it triggers a cascade of adaptations.

    Fluids that gravity normally pools in the legs shift upward, producing puffy faces and congestion for the first days. Bones lose density at a rate comparable to advanced osteoporosis, concentrated in the load-bearing structures that no longer bear load. Muscles atrophy, particularly in the legs and back.

    The countermeasure is exercise, treated as a non-negotiable part of the schedule: around two hours a day on a treadmill with a harness to hold the runner down, a stationary cycle, and a resistance device that simulates weightlifting using vacuum cylinders.

    Vision changes have emerged as one of the more concerning long-duration effects, apparently related to pressure changes from the fluid shift, and some cases have not fully reversed after return. Radiation exposure is elevated, since the station sits above most of the atmosphere though still within the protection of Earth’s magnetic field.

    Astronauts return measurably taller, having lost the spinal compression that gravity imposes all day on the ground. It does not last.

    Ordinary tasks, redesigned

    Every routine activity had to be reconsidered.

    • Sleeping happens in a padded booth roughly the size of a phone box, in a sleeping bag attached to the wall. Orientation is irrelevant; there is no down.
    • Eating works because surface tension holds liquids in place. Most food is rehydrated or thermostabilised, eaten from packages, and seasoning is supplied as liquid so it does not drift into equipment.
    • Washing is done with rinseless soap and towels. There is no shower, since water would not drain.
    • The toilet uses airflow instead of gravity, with separate systems for solid and liquid waste. Urine is recovered and processed back into drinking water, which recycles a large fraction of the station’s supply.
    • Sixteen sunrises and sunsets per day make natural light cues useless, so the crew works on coordinated universal time with a carefully managed schedule.

    Where the time goes

    A typical day runs roughly twelve hours, with science and maintenance dominating.

    The station’s purpose is to be a laboratory, and the research spans protein crystal growth in the absence of convection, combustion physics without buoyancy, materials science, plant biology, and long-term studies of the human body itself. Much of it is work that cannot be done on the ground because gravity interferes.

    Maintenance is a larger share than most people assume. The station is an ageing spacecraft with life support, thermal control, power, and communication systems that require constant attention. Filters get cleaned. Pumps get replaced. Occasionally something breaks that requires a spacewalk, which involves hours of preparation, a suit that functions as a personal spacecraft, and a task list rehearsed extensively in a pool on Earth.

    The cooperative part

    The station is assembled from modules built by multiple space agencies and operated jointly by the United States, Russia, Europe, Japan, and Canada. Segments are structurally and functionally interdependent — power, propulsion, and life support are shared across national boundaries by design.

    It has continued operating through periods of considerable political friction on the ground, which is either a testament to the durability of technical cooperation or simply a consequence of the fact that the modules cannot be separated. Probably both.

    The end of the programme

    The station has a finite life. Structural fatigue accumulates, and hardware designed decades ago becomes progressively harder to support. Current planning points toward retirement around the end of this decade, with a controlled deorbit over the remote Pacific.

    Several commercial stations are in development to succeed it. Whether the handover is seamless is an open question — but the goal is that the streak of continuous human presence in orbit, now well past twenty-five years, does not break.

  • The New Space Race: Commercial Companies Reaching for Orbit

    The New Space Race: Commercial Companies Reaching for Orbit

    For half a century, orbit was reachable only by governments. Rockets were national programmes, built by contractors on cost-plus terms, flying at a cadence measured in a handful of launches per agency per year.

    That arrangement has been substantially dismantled. The change was not primarily technological — it was contractual.

    What actually changed

    The pivotal shift was in how launch is bought.

    Under traditional cost-plus contracting, an agency specifies the vehicle in detail, funds its development, absorbs overruns, and owns the result. The contractor’s incentive to reduce cost is weak, because reduced cost means reduced revenue.

    Under fixed-price service contracts, an agency states what it needs delivered and pays on completion. The supplier owns the vehicle, keeps the savings from making it cheaper, and can sell the same service to other customers. Development risk shifts to the supplier, which changes the calculus on everything from testing philosophy to design iteration.

    Programmes that bought cargo and later crew transport to the space station on this model demonstrated that it could work for high-stakes missions, not just secondary payloads. Once that was established, the model spread.

    The technical enabler

    Contracting alone would not have been enough without the cost reductions that reusability delivered.

    Recovering and reflying first stages cut the marginal cost of a launch substantially and, just as importantly, raised the achievable flight rate. When the constraint moves from building a new rocket to refurbishing an existing one, annual launch counts can climb into ranges that were previously infeasible.

    Manufacturing changed too. Vertical integration — building engines, avionics, and structures in-house rather than through layered subcontracts — shortened iteration cycles. Additive manufacturing made complex engine components producible in days rather than months. Commercial off-the-shelf electronics, flown in redundant configurations rather than individually radiation-hardened at enormous cost, cut avionics budgets dramatically.

    The industry did not get better at building rockets so much as it got better at building rockets repeatedly.

    What the market looks like now

    The sector has diversified well beyond launch.

    • Heavy and medium launch is competitive, with several operators and more vehicles in development, including from established aerospace firms responding to the new entrants.
    • Small launch is a crowded field serving satellites too small or too schedule-sensitive to wait for a rideshare slot. Consolidation here is ongoing and some operators have not survived.
    • Satellite constellations in low Earth orbit now number in the thousands of spacecraft, providing broadband connectivity and Earth observation at a scale that would have been unaffordable a decade ago.
    • Crew transport to orbit is a commercial service, flying both agency astronauts and private customers.
    • Lunar delivery has been opened to commercial providers, with mixed results — several attempted landings have failed, which is a reasonable outcome for an early-stage market and a poor one for the payloads involved.
    • Commercial space stations are in development to succeed the International Space Station.

    The parts that are overstated

    A few caveats are worth holding onto.

    Government money remains central. Most commercial space companies derive a large share of revenue from public contracts, and the anchor customers for crewed flight, lunar delivery, and national security launch are all governments. This is a restructured public-private relationship, not a private sector operating independently.

    Profitability is uneven. Launch is capital-intensive with long development cycles, and the number of companies that have reached sustained profitability is small relative to the number that have raised money.

    Constellation economics are unproven at the largest scales. Building and continuously replacing thousands of satellites with limited operational lifetimes is an enormous recurring cost, and whether the subscriber revenue supports it over the long run is still being tested.

    The externalities

    Rapid growth has produced problems that are now being taken seriously.

    Orbital debris accumulates, and low Earth orbit is finite. Collision avoidance manoeuvres are increasingly routine, and the worst-case scenario — a cascade of collisions generating debris faster than it decays — would render valuable orbits unusable for generations.

    Astronomers have raised well-documented objections about satellite constellations streaking long-exposure images and interfering with radio observations. Mitigations including darkening treatments and orientation changes have helped but not eliminated the issue.

    Regulation has lagged. Licensing regimes for launch, spectrum, and re-entry were designed for a far lower flight rate, and coordination between national authorities on debris mitigation remains weak.

    Where it is heading

    The near-term trajectory points toward higher flight rates, further cost reductions if fully reusable vehicles reach operational service, and an expanding set of activities in orbit beyond communications and imaging.

    Whether the market is large enough to support the number of companies currently pursuing it is a different question. Some consolidation seems likely. But the structural change — that reaching orbit is a service purchased from competing suppliers rather than a capability possessed by a handful of states — appears durable.