Satellite imagery is a tool for governments, insurers and big farms: Google Earth shows a frozen mosaic that can be years old, and crop monitoring dashboards like EOS or Sentinel Hub speak in indices and polygons. Nobody turns the free weekly pass over one family's farm into a plain-language letter for the people who left it. Home From Orbit is the first product where the satellite writes to the diaspora, about a place they love, every week.
The data it runs on
Source: Sentinel-2 Level-2A surface reflectance from the European Copernicus programme, free and open. Bands at 10 m (red, green, blue, near-infrared) give true colour, greenness (NDVI) and a water index (NDWI).
Access: the Copernicus Data Space Ecosystem STAC API or the free Sentinel-2 archive on AWS Open Data, clipped to a 1 km square around the pin with a cloud mask from the scene classification layer.
Limits: a new pass roughly every 5 days, and clouds can hide whole weeks (monsoon Kerala is cloudy for months). 10 m pixels show fields, rivers, roads and big roofs, never people, cars or faces.
Fallback: when clouds win, Sentinel-1 radar (also free) sees through them; the letter says so honestly. If both fail, the letter says "no clear look this week" and shows the last clear view.
1. The mission
Give everyone who left home a window back to it. Every week, a short, honest letter from orbit about the place you love, so a nurse in London knows the rains came to her father's farm before he even calls.
2. Why people can't resist it
Homesickness with a schedule. A letter that arrives every Sunday about the one place you think about most.
Seeing what your family describes. "We harvested on Thursday" becomes a field that turned from green to gold on your screen.
Something to say in the family chat. Each letter is a reason to call home: "Did the river reach the tomatoes?"
3. How it works for real
Pin: user drops a pin; we store a 1 km square, never an address.
Fetch: a weekly job pulls the clearest Sentinel-2 scene of the week (Sentinel-1 radar if cloudy) and computes NDVI and NDWI per 10 m pixel.
Detect change: plain code segments fields from multi-week NDVI, then flags parcels and water edges that changed beyond a threshold. No AI needed for the numbers.
Describe: a vision model (Gemini Flash or a Claude model via OpenRouter) gets this week's and last week's image plus the change table and labels what it sees: "harvested", "flooded", "new track".
Write: a frontier LLM (Claude or GPT) writes a 120 word letter in plain words, in the family's language (Hausa, Malayalam, Polish, English), with only claims the change table supports.
Deliver: email, WhatsApp or push every Sunday, with a share card. Optional TTS reads it aloud for grandparents.
4. Cost per use
Free imagery; one vision call a week. About $0.003 for the vision call, $0.002 for the letter, a fraction of a cent for compute. Under $0.03 per place per month.
Free: one place, a letter every two weeks. Family ($3 a month): weekly letters, up to 3 places, 10 relatives, archive, letters in two languages, a printed year-in-orbit poster at cost.
5. Growth loop
Every letter is written to a family, so the subscriber adds siblings and cousins on day one. Each relative who opens a letter is offered their own place: the in-laws' village, the school they went to. Share cards travel in diaspora WhatsApp groups.
6. Risks and guardrails
Surveillance: 10 m resolution cannot see people, and we never buy sharper commercial imagery. Pins are fuzzed to the square; no live tracking.
False alarms: the letter never says "your house flooded". It says what the pixels show and suggests calling home.
Disputed land: no boundaries or ownership claims, only "the fields north of the pin".
Attribution: "Contains modified Copernicus Sentinel data" on every letter, as the licence asks.
7. MVP build order
Pin to 1 km square, fetch the last 8 clear Sentinel-2 scenes, render true colour and NDVI.
Week-to-week change table per parcel and water edge.
Letter prompt with the change table as the only allowed facts, plus a one-tap "that's wrong" flag.
Sunday email with share card, then add relatives by link.