TUNGSTEN VALLEY - This month we begin a three-part series on getting people to Mars; landing people on Mars; and living on Mars.

Why? Because the obscene budget bill that Congress just passed has mostly disposed of our space science, leaving NASA to mostly just support a megalomaniacal, short-fuse crewed trip to Mars.

The Red Planet is good for exploring with robots. It’s a terrible place for people to try to visit. Robots are obedient; they never get tired; and nobody’s emotionally attached to them. There’s no logical reason to send astronauts to Mars other than to satisfy personal whims.

In any event, how do we (either robots or people) fly to and from Mars? Well, we don’t just burn a rocket engine throughout the trip, on a beeline through space. (Although there are things called ion engines that do generate continuous, low thrust nearly forever.)

Rather, for interplanetary trips we only fire our rocket engine twice, once to accelerate at departure and then a second time to brake at our destination. In between, we wear pajamas and coast elegantly through space on a free-falling path that’s a slice of a circle, ellipse, or hyperbola.

The minimum required rocket power connects the earth with Mars on a half-ellipse that grazes both planets’ orbits. It’s called a Hohmann route, after Walter Hohmann who published it in 1925. (Hohmann was a principled German who declined involvement with Nazi-enmeshed rocket builders like Werner Von Braun. He died in Essen in 1945 during Allied bombing raids.)

Hohmann routes trade efficiency for slowness. To get there faster, you need a larger rocket that does a bigger pair of burns. The diagram compares a Hohmann transfer to a higher-energy, speedier trip.

Mars travel times range from nine months (Hohmann) to around six months for a Saturn V or Starship-type vehicle. That’s just getting there; double it for returning home. And in-between, you have to wait at Mars for weeks or months until the planets’ geometry aligns for a favorable return.

All told, a typical Mars round trip requires fourteen months to two years.

That’s longer than anyone has continuously been in space, only a handful of people having ever been at a space station for more than six months. Moreover, in earth orbit people are shielded from cancer-causing space radiation by our planet’s magnetic field. On a Mars trip, travelers will be bombarded with continuous high radiation doses.

Another yet-to-be solved problem for a crewed trip is how to maintain ultra-cold fuel and oxidizer (say, liquid methane and oxygen) for a year or two, without having them warm up and boil off. Powered freezing systems have been imagined but not built or tested.

Consumables are another huge challenge. Water and air can be recycled (but again, no systems have been built for a Mars trip) but food cannot. Six person-years of food would be needed for three people for two years.  Even clothes are an issue: There are no spaceship washing machines.

In earth orbit, dirty clothes go overboard with every fresh set from the ground. On a Mars trip they’ll need enough clothes for a couple of years.

The list goes on. Suffice to say, the unsolved challenges of long travel times to and from Mars are massive.

Lastly, there are immutable cosmic timetables for interplanetary geometries. The next Mars-launch opportunity is late 2026; next after that is the cusp of 2028-2029. The upcoming window is just over a year out. The clock, as they say at Mission Control, is running.

August Fun Astro-Fact: Using Tycho Brahe’s precise, multi-decade observations of Mars, Europe’s finest mathematician, Johannes Kepler, published in 1609 the clinching technical proof that Mars and the earth orbit the sun.

In August skies:

Solar Max: The 11-year sunspot cycle peaked in July, but the next few months are still good for seeing sunspots. For safe viewing, go to https://skyandtelescope.org/observing/observing-the-sun/.

The sun begins the month in Cancer, entering Hydra/Leo on August 10. At mid-month, days and nights are 13.5 and 10.5 hours long, respectively.

The moon’s dates are: First Quarter August 1; Full (Sturgeon or Corn Moon) August 9; Last Quarter August 15; New August 22; First Quarter (again) August 30.

August Meteor Showers: The Perseids (parent Comet Swift-Tuttle) and kappa-Cygnids (parent possibly Asteroid 2001 MG1) peak on August 13 and 18. The famous Perseids are best seen shortly before dawn. The k-Cygnids peak around 11 p.m.

Best Sky Viewing Nights (Minimal Moon): August 15-30.

Sunset (Mid-Month): Deneb is high in the east; Vega is nearly overhead; Altair is mid-sky in the northeast. Hercules with its striking M-13 globular cluster is overhead. Libra (twin bright stars Zubeneschamali and Zubenelgenubi) is low in the southwest. Antares is due south in Scorpius.

Midnight (Mid-Month): The Teapot in Sagittarius, marking the Milky Way’s center, glows in the south-southwest. Scan its wonders with binoculars or a telescope.

Sunrise (Mid-Month): The Gemini twins are low in the east. Our nearest neighbor galaxy, M-31 Andromeda, gives great binocular viewing directly overhead.

Mercury, in Cancer, is at maximum elevation above the eastern horizon, ahead of sunrise, on August 10.

Venus, in Gemini, is the Morning Star in the eastern sky before sunrise.

Mars, in Virgo, is low in the west at sunset.

Jupiter, in Gemini, conjuncts spectacularly with Venus just before sunrise in the eastern sky on August 11.

Saturn, in Aquarius, rises at 9:30 p.m.; is high in the southeast at 2 a.m.; and is in the southwest at sunrise. Find it in binoculars and then pivot upward to see Neptune.

Notable Space Missions: The US Space Force launches a robotic spaceplane X-37B Orbital Test Vehicle Mission from Cape Canaveral on August 21. 

Frank Sanders, a spectrum scientist, takes astronomy-related inquiries at backyardastronomy1@gmail.com.