diff --git a/spaceros/Earthfile b/spaceros/Earthfile
index 442343d..192078d 100644
--- a/spaceros/Earthfile
+++ b/spaceros/Earthfile
@@ -21,7 +21,7 @@ earthfile:
 setup:
   # Disable prompting during package installation
   ARG DEBIAN_FRONTEND=noninteractive
-  
+
   # The following commands are based on the source install for ROS 2 Rolling Ridley.
   # See: https://docs.ros.org/en/ros2_documentation/rolling/Installation/Ubuntu-Development-Setup.html
   # The main variation is getting Space ROS sources instead of the Rolling sources.
@@ -74,7 +74,6 @@ setup:
   ENV HOME_DIR=/home/${USERNAME}
   ENV SPACEROS_DIR=${HOME_DIR}/spaceros
   ARG IKOS_DIR=${HOME_DIR}/ikos
-  ARG REPOS_FILE_URL="https://raw.githubusercontent.com/space-ros/space-ros/main/ros2.repos"
   ENV ROSDISTRO=humble
 
   # Create a spaceros user
@@ -92,9 +91,40 @@ setup:
   RUN sudo add-apt-repository ppa:kisak/kisak-mesa
   RUN sudo apt update && sudo apt upgrade -y
 
+spaceros-artifacts:
+  # we must run it in a separate container, so that downstream tasks can be cached if vcs file does not change
+  FROM ubuntu:jammy
+  RUN apt-get update && apt-get install -y git wget
+
+  # main purpose of this command is to make sure that the git ls-remote results are not cached
+  RUN --no-cache echo "Cloning spaceros repo artifacts"
+
+  # current git branch, prefilled by earthly: https://docs.earthly.dev/docs/earthfile/builtin-args
+  ARG EARTHLY_GIT_BRANCH
+
+  ARG SPACEROS_REPO_URL="https://github.com/space-ros/space-ros.git"
+  # if current local branch does not exist in target repo then use main. note that branch supplied from CLI overrides this behavior.
+  ARG SPACEROS_GIT_REF="$( [ -n \"$(git ls-remote $SPACEROS_REPO_URL $EARTHLY_GIT_BRANCH)\" ] && echo $EARTHLY_GIT_BRANCH || echo 'main' )"
+  # get exact commit hash. this makes sure that build will be re-triggered when new commit is pushed 
+  ARG _GIT_COMMIT_HASH = "$(git ls-remote $SPACEROS_REPO_URL $SPACEROS_GIT_REF | cut -f 1)"
+
+  # this means that branch specified by user from CLI does not exist
+  IF [ -z ${_GIT_COMMIT_HASH} ] 
+    RUN echo "Specified branch ${SPACEROS_GIT_REF} does not exist" && exit 1
+  END
+
+  IF [ $SPACEROS_REPO_URL = "https://github.com/space-ros/space-ros.git" ] 
+    # run wget because main repo's host is known + it is public 
+    RUN wget https://raw.githubusercontent.com/space-ros/space-ros/${_GIT_COMMIT_HASH}/ros2.repos
+  ELSE
+    GIT CLONE --branch ${_GIT_COMMIT_HASH} ${SPACEROS_REPO_URL} .
+  END
+  SAVE ARTIFACT ros2.repos
+
 sources:
   FROM +setup
-  COPY github.com/space-ros/space-ros:earthly-wrapper+repos-file/ros2.repos ros2.repos
+  COPY +spaceros-artifacts/ros2.repos ros2.repos
+
   RUN mkdir src
   RUN vcs import src < ros2.repos
   SAVE ARTIFACT src AS LOCAL src
diff --git a/spaceros/README.md b/spaceros/README.md
index 1abf83e..4cae5ab 100644
--- a/spaceros/README.md
+++ b/spaceros/README.md
@@ -15,6 +15,12 @@ $ ./build.sh
 
 The build process will take about 20 or 30 minutes, depending on the host computer.
 
+The build process defaults to cloning the `ros2.repos` file from [spaceros](https://github.com/space-ros/space-ros) repository. It looks for a branch with the same name as the current local branch; if it doesn't find one, it falls back to cloning from the main branch. For testing purposes, you can customize both the spaceros repository URL and the branch name by modifying arguments defined in the [Earthfile](./Earthfile).
+Example:
+```bash
+earthly +image --SPACEROS_REPO_URL="https://github.com/my-org/my-spaceros-fork.git" --SPACEROS_GIT_REF="my-branch-name"
+``` 
+
 ## Running the Space ROS Docker Image in a Container
 
 After building the image, you can see the newly-built image by running: